U.S. patent application number 11/276173 was filed with the patent office on 2006-06-15 for information display system, display device, display device drive method and display apparatus.
This patent application is currently assigned to FUJITSU LIMITED. Invention is credited to Masaki Nose, Tomohisa SHINGAI, Junji Tomita, Fumio Yamagishi.
Application Number | 20060124897 11/276173 |
Document ID | / |
Family ID | 34260130 |
Filed Date | 2006-06-15 |
United States Patent
Application |
20060124897 |
Kind Code |
A1 |
SHINGAI; Tomohisa ; et
al. |
June 15, 2006 |
INFORMATION DISPLAY SYSTEM, DISPLAY DEVICE, DISPLAY DEVICE DRIVE
METHOD AND DISPLAY APPARATUS
Abstract
A display apparatus comprises a display unit capable of
continuing a display even after the power is shut off, a short
range communication unit for receiving display data provided
externally and a display control unit for the received data, while
an information display apparatus comprises a storage unit for
storing display data and a communication unit for transmitting the
display data over to the display apparatus, and further the
information display apparatus comprises a mechanical quick release
mechanism for mounting the display apparatus onto the own apparatus
for example, in order to configure a system, which is capable of
detachable attachment, between the display apparatus having no
power supply and the information display apparatus, such as a
wireless terminal, which sends display data and power to the
display apparatus.
Inventors: |
SHINGAI; Tomohisa;
(Kawasaki, JP) ; Tomita; Junji; (Kawasaki, JP)
; Nose; Masaki; (Kawasaki, JP) ; Yamagishi;
Fumio; (Kawasaki, JP) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700
1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
FUJITSU LIMITED
Kawasaki
JP
|
Family ID: |
34260130 |
Appl. No.: |
11/276173 |
Filed: |
February 16, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/JP03/11314 |
Sep 4, 2003 |
|
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11276173 |
Feb 16, 2006 |
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Current U.S.
Class: |
252/299.01 |
Current CPC
Class: |
G02F 2203/34 20130101;
G09G 2380/06 20130101; G09G 2340/0457 20130101; G09G 2300/026
20130101; G09G 2300/0456 20130101; H04N 1/00901 20130101; G06F
3/147 20130101; G09G 2320/041 20130101; G09G 3/3651 20130101; H04N
1/00891 20130101; G09G 2310/0205 20130101; H04N 2201/0084 20130101;
G02F 1/13718 20130101; G09G 2300/0486 20130101; H04N 1/00342
20130101; H04N 1/00893 20130101; G09G 3/3674 20130101; H04N
2201/0096 20130101; G09G 2310/08 20130101; G02F 1/133377 20130101;
H04N 1/00307 20130101; H04N 1/00885 20130101; H04N 2201/0089
20130101; G09G 3/3696 20130101 |
Class at
Publication: |
252/299.01 |
International
Class: |
C09K 19/52 20060101
C09K019/52 |
Claims
1. An information display system, including: a display apparatus
which comprises a display unit capable of data display even if a
power supply is cut off, a short range communication unit for
carrying out a short range communication in order to receive data
to be displayed externally, and a display control unit for
controlling a display performed by the display unit in response to
received data by the short range communication unit; and display
data retention apparatus which comprises a storage unit for holding
display data, and a communication unit for transmitting display
data over to the display apparatus at least within a short range in
response to a storage content of the storage unit.
2. The information display system according to claim 1, wherein
said display data retention apparatus further comprises a long
range communication unit, capable of long range communication
unlike said communication unit, for acquiring display data
externally, wherein the communication unit transmits display data
acquired by the long range communication unit over to said display
apparatus.
3. The information display system according to claim 1, wherein
said display apparatus further comprises a mechanical quick release
unit for mounting the apparatus itself onto a person or
clothing.
4. The information display system according to claim 1, wherein
said display data retention apparatus further comprises a display
unit having a smaller display area than a display unit comprised by
said display apparatus, and a mechanical quick release unit for
mounting the display apparatus onto the own apparatus.
5. The information display system according to claim 1, wherein
said display data retention apparatus further comprises a display
unit having a smaller display area than a display unit comprised by
said display apparatus, and said display apparatus further
comprises a mechanical quick release unit for mounting the display
data retention apparatus onto the apparatus itself.
6. The information display system according to claim 1, wherein
said short range communication unit comprised by display apparatus
further receives power for displaying and display control
information, in addition to said data to be displayed over from
said display data retention apparatus.
7. A display device, in the display device having two substrates,
between which a liquid crystal is injected, comprises partition
walls with a structure for keeping plural colors of liquid
crystals, which are injected between the two substrates, from
touching one another.
8. The display device according to claim 7, wherein a surface of
said partition walls in contact with said substrate has an adhesive
force with the substrate.
9. The display device according to claim 7, wherein said plural
colors of liquid crystals are the ones each forming a cholesteric
phase.
10. The display device according to claim 7, wherein said plural
colors of liquid crystals make an additive color of white.
11. A display apparatus, comprising: a first display device having
a transmission and a reflection mode, and capable of switching
display contents, and a reflective second display device for
displaying a fixed image or character and enabling a viewing of
display content through the first display device.
12. The display apparatus according to claim 11, wherein said
second display device is a body which is printed or handwritten by
a character and/or image and is detachably attached to said first
display device.
13. The display apparatus according to claim 12, wherein said first
display device has the function of being capable to change a
display range according to a position and shape of a fixed image or
character on said detachably attached second display device.
14. A display apparatus, in the display apparatus using a liquid
crystal display comprising a temperature compensation unit for
changing, in response to temperature, two kinds of peak values of
drive voltage wave forms corresponding to two stable states of the
liquid crystal.
15. The display apparatus according to claim 14, wherein said
liquid crystal is the one forming a cholesteric phase, and said
temperature compensation unit changes a peak value of a drive wave
form corresponding to a focal conic state as one of said two stable
states along a straight line connecting the average of the upper
and lower limit values of the peak values of the drive wave form at
the lower limit within an operating temperature range and the
average of the upper and lower limit values of the peak values of
the drive wave form at the higher limit within the operating
temperature range.
16. A display apparatus, in the display apparatus having a coil
furnished in order to receive an external high frequency magnetic
field, comprising: a display-use power supply unit for supplying a
display-use voltage by rectifying a high frequency voltage induced
by the coil, and a logic-use power supply unit for supplying
circuits other than the one for display use with a voltage by
rectifying a high frequency voltage induced by the coil.
17. The display apparatus according to claim 16, wherein said coil
comprises an intermediary tap with one end of the coil being
grounded, a for-resonance capacitor is connected between the
intermediary tap and ground, said logic-use power supply unit
rectifies a voltage across the for-resonance capacitor, and said
display-use power supply unit rectifies a voltage across the other
end of the coil and the intermediary tap.
18. A display apparatus, in the display apparatus comprising a
display unit for performing a data display by using power supplied
externally by noncontact means, comprising a display function
control unit for controlling a display function of the display unit
in response to supplied electric power externally.
19. A display apparatus, in the display apparatus comprising a
display-use power supply which uses a part of power supplied
externally by noncontact means, and a logic-use power supply for
supplying circuits other than the one for display use with power by
using a part of the power, comprising a current regulation unit for
regulating an output current of the display-use power supply in
response to a voltage drop of the logic-use power supply.
20. A display device drive method for use in a matrix type display
apparatus using a liquid crystal which forms a cholesteric phase,
comprising the steps of setting some of scanning electrodes for a
reset and writing lines to a selection state and a pause line to a
non-selection state, respectively; and providing a writing data
signal to a signal electrode side while shifting the reset, pause
and writing lines, respectively.
21. The display device drive method according to claim 20, wherein
a writing alternate signal provided to a reset and writing lines in
said selection state reverses polarities within a time
corresponding to one line, and also has a period corresponding to
two lines.
22. A display device drive method for use in a matrix type display
apparatus using a liquid crystal which forms a cholesteric phase,
comprising the steps of detecting a plurality of lines, in which
data patterns to be displayed are the same, from among a plurality
of lines on a display screen of the display apparatus; and writing
the same pattern data in bulk by selecting the detected plurality
of lines simultaneously and providing data of the same pattern to
signal electrodes.
23. The display device drive method according to claim 22, wherein
the maximum number of the plurality of lines to which writing in
bulk is carried out is inversely proportional to the spatial
frequency of the same pattern data.
24. A display device drive method for use in a display apparatus
using a liquid crystal device, comprising the steps of converting
image data to be written in a liquid crystal device into image data
having n-number of gray scales; extracting a pixel of each gray
scale level after conversion; and forming, for the extracted
pixels: a sub-image 1 which is formed by converting the pixels on
the least bright gray scale level 1 (i.e., on black level) and n-th
least bright gray scale level n (i.e., on white level) into black
and white levels, respectively, a sub-image 2 which is formed by
converting the ones between the least bright gray scale level 1 and
the second least bright gray scale level 2 into a black level
followed by combination with the gray scale level n, . . . so on
and so forth . . . , and a sub-image (n-1) which is formed by
converting the ones between the least bright gray scale level 1 and
(n-1)-th least bright gray scale level (n-1) into a black level
followed by combination with the gray scale level n; wherein a
writing starts with the sub-image 1, followed by the sub-image 2,
so on and so forth, and sub-image (n-1) in that order.
25. A display device drive method for use in a display apparatus
using a liquid crystal device, comprising the steps of converting
image data to be written in a liquid crystal device into image data
having n-number of gray scales; extracting a pixel of each gray
scale level after conversion; and forming, for the extracted
pixels: a sub-image 1 which is formed by converting the pixels on
the brightest gray scale level 1 and n-th least bright gray scale
level n into white and black levels, respectively, a sub-image 2
which is formed by converting the ones between the brightest gray
scale level 1 and the second brightest gray scale level 2 into a
white level followed by combination with the gray scale level n, .
. . so on and so forth . . . , and a sub-image (n-1) which is
formed by converting the ones between the brightest gray scale
level 1 and (n-1)-th brightest gray scale levels (n-1) into a white
level followed by combination with the gray scale level n; wherein
a writing starts with the sub-image 1, followed by the sub-image 2,
so on and so forth, and sub-image (n-1) in that order.
26. A display apparatus, comprising: a display unit for carrying
out data display; a storage unit for storing information relating
to an acquisition method for data to be displayed and one relating
to a displaying form for an acquired display data; and a control
unit for controlling acquisition of display data externally, and
display of the display data in the display unit, both in accordance
with storage content of the storage unit.
27. The display apparatus according to claim 26, wherein said
display unit is capable of continuing data display even if the
power is shut off.
28. The display apparatus according to claim 26, wherein said
control unit carries out an automatic startup of the display
apparatus in response to an instruction provided either externally
or internally, acquires display data from said external entity and
displays the display data, followed by transitioning the display
apparatus automatically to a ready state.
29. The display apparatus according to claim 26, further comprising
a data acquisition unit for acquiring display data yet to be
acquired at a communication restart if the communication with an
external entity is interrupted in the middle of acquiring the
display data from the external entity.
30. The display apparatus according to claim 26, further comprising
a rewriting inhibit unit for inhibiting a rewriting of data
displayed by said display unit.
31. The display apparatus according to claim 26, further comprising
a nonvolatile memory unit for storing data for one page or more as
the data allowing said display unit to display.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of PCT application No.
PCT/JP2003/011314, which was filed on Sep. 4, 2003.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an information display
system comprising mobile equipment for example and an apparatus for
displaying discretionary data provided by such equipment, a display
device, display device drive method and display apparatus used for
such an information apparatus, and specifically to a system
comprising a wireless terminal for example and a noncontact IC
card, a display device and its drive method using a cholesteric
liquid crystal, et cetera, capable of retaining a display even if
electric power (NB simply "power" hereinafter unless otherwise
noted) is cut off, and a display apparatus using electronic paper
with such a memory property for example.
[0004] 2. Description of the Related Art
[0005] There is a requirement of enlarged display for display
information on a mobile phone, PDA, digital camera, et cetera. One
method to address this has been to enlarge a part of the display of
such a terminal. This method naturally precludes a single view of
the whole image at once, requiring operations such as cumbersome
scrolling. Another method is to send image information wirelessly
to equipment such as a personal computer (PC), TV, et cetera,
equipped with a large screen display and thereby display the image
by furnishing a mobile terminal with a short range wireless
communication means such as Bluetooth, infrared or a wireless LAN.
Or a method for displaying by a large screen display by
transmitting the image by using a wired interface connection
function such as USB, IEEE1394, et cetera, in place of wireless
transmission. Such enlarged display methods are not suitable for
mobile equipment in mobile environments such as away from the
office or home, since they require either an AC power supply or
some kind of battery, and such apparatuses per se are heavy.
[0006] There is a concept of connecting a light weight, low power
consumption enlarged display to a mobile terminal as a display
method in a mobile environment while avoiding the above described
inconveniences. Such attempts have been made by using lightweight
low power electronic paper. Such a method, however, is
disadvantageous since it is an electrical contact connection. In
summary: 1) a continuous connection makes the actual size of a
mobile terminal large; 2) use of a connection brings about
degradation due to a fatigue of the electric contact; or 3) display
loss after disconnection, or possibly equipping a battery for
preventing a display loss. Equipping the display unit with a
battery not only causes the inconvenience of changing the battery
for the display unit or charging the battery, but also an increase
in the thickness and/or weight of the display. Accordingly a mobile
display system whose terminal itself is substantially small, which
has an enlarged screen display, and which allows hands free
operation, while solving the problems as described above is
required.
[0007] In the meantime, there is a requirement for printing out
discretionary display information carried by a mobile phone, PDA,
digital camera, et cetera, away from home, the office, or in a the
location of a visit. Battery operation mobile printer apparatuses
are commercially available for meeting such a requirement, which
are faced with problems such as the weight and size of such
equipment as well as supply of paper or batteries, however. The
expectation is to have a display a la paper print without using a
printer in a state of detachment from a mobile terminal.
[0008] There are conventional techniques using a contact type IC
card or an RF (radio frequency) tag, and reference documents
concerned with a noncontact IC card, which utilizes short-range
wireless communication as follows. A patent document 1 has
disclosed an IC card capable of rewriting the display content of a
display.
[0009] Each of the patent documents 2, 3 and 4 has disclosed an IC
card having an electric power supply for display, with a solar
battery in the patent document 2, a lithium battery in the patent
document 3 and an auxiliary power supply such as solar battery in
the patent document 4.
[0010] The patent documents 5 and 6 deals with a memory capable
display device which retains a displaying content even after the
power is cut off, hence there is no need of an auxiliary power
supply such as a solar battery. The patent document 5 deals with a
ferroelectric liquid crystal display ("LCD" hereinafter) device and
electro-chromic display device for example, while the patent
document 6 proposes a use of a cholesteric-nematic phase transition
type liquid crystal ("LC" hereinafter).
[0011] [Patent document 1] Japanese utility model publication
H07-30384: "IC card"
[0012] [Patent document 2] Japanese laid-open patent application
publication No. S62-242592: "IC card"
[0013] [Patent document 3] Japanese laid-open patent application
publication No. S63-3393: "Card processing system with display
function"
[0014] [Patent document 4] Japanese laid-open patent application
publication No. 2003-6590: "Information storage medium with
auxiliary power supply"
[0015] [Patent document 5] Japanese laid-open patent application
publication No. H10-93484: "Data carrier"
[0016] [Patent document 6] Japanese laid-open patent application
publication No. 2000-113137: "Noncontact information storage
display method and noncontact information storage display
medium"
[0017] These kinds of short range wireless generally exchange
information wirelessly with a non-powered IC card by way of an IC
card reader/writer equipped with a stationary terminal. It is
fundamentally possible to record or display by providing a
displaying/recording unit power and display information if a card
and a writer are mutually in proximity. However, there has
conventionally been no well designed convenient display system
linking to a mobile terminal by using a noncontact wireless
technique which has actually been retarded for technical reasons,
e.g., shortage of power required for recording voltage, memory
retention capability and recording speed for example, hence failing
to accomplish a display on a noncontact mobile terminal to date.
Accordingly, what have been desired are a convenient display system
and an electronic paper which are suitable for mobile usage as an
enlarged display by transmitting discretionary display information
from a mobile terminal by utilization of a noncontact wireless
technique.
[0018] Electrophoresis, while being seen as a powerful memory
capable medium, its memory holding capability fundamentally
contradicts high-speed drivability and low voltage drivability
because the technique consists of attracting white or black
electro-statically charged particulates from among those suspended
in a white liquid contained by a capsule. Therefore, it is very
difficult to use the technique for non-powered recording.
Electrochromic memory is a memory storage method utilizing a
chemical reaction and requiring a large amount of power for
recording, and hence is difficult to use in wireless recording.
Meanwhile, with regards to a memory capable LC, a ferroelectric
memory liquid crystal medium, while rendering high-speed recording,
is faced with the problems of inadequate brightness in a reflective
white display due to the use of polarization film and loss of
display due to physical shock.
[0019] As a memory capable LC, there is a cholesteric-nematic phase
transition type LC device which has been proposed by the above
noted patent document 6. This material, utilizing light scattering,
has been faced with the problems of being limited to low contrast
and requiring a bias voltage for holding a display stable.
[0020] In comparison to the above, a cholesteric LC (including a
chiral-nematic LC), having a selective reflectivity, i.e.,
reflecting light of a certain wavelength selectively, reflects an
optical wavelength according to the layer pitch of a liquid
crystal, thereby indicating a monochromatic color. Accordingly, a
layered structure has been proposed, as with a below noted patent
document 7, to make it polychromatic.
[0021] [Patent document 7] Japanese laid-open patent application
publication No. H09-160066: "Reflective liquid crystal display
device"
[0022] FIG. 1 exemplifies a conventional configuration of a layered
LC device using a cholesteric LC. In FIG. 1, upper and lower
substrates 201 sandwich three layers of LC 204, 205 and 206 each
being adhered by way of a transparent electrode 202, thereby
structuring an LC device. This structure, however, having many
interfaces producing a lot of optical noise, suffers a reduced
display contrast. There is also the problem of having many
components, resulting in a high cost apparatus.
[0023] In other words, the cholesteric LC indicates a certain
monochromatic color and, if two LCs are combined, the desired color
cannot be reflected because the colors are mixed easily. A mixture
of two or more LCs makes an intermediary color or a state of no
reflectance. There is a capsule structure for sealing an LC within
a capsule as a method for separating LCs, which has been faced with
the problems of reduced contrast due to optical noise and an
increased drive voltage, both influenced by the interface and
thickness of the capsule, hence its use is disadvantageous in a
display apparatus, and the difficulty in laying desired capsules
for desired pixels.
[0024] Let us then describe problems associated with the power
supply circuit, et cetera, in the case of using such a cholesteric
LC for a non-powered display apparatus such as a noncontact type IC
card and electronic paper. In a common non-powered noncontact IC
card, et cetera, a method used is to display by receiving power
therefor along with data from a mobile terminal, IC card
reader/writer, et cetera for example, by way of short range
wireless, and therefore the power value usable for a power supply
is small, hence requiring current regulation, et cetera, for the
power supply circuit.
[0025] In particular, the cholesteric LC requires two types of
drive wave forms with different peak values for driving two stable
states respectively, i.e., the planar state and the focal conic
state, as described later. Moreover, a drive voltage of
approximately 40 volts is required to for the planar state, which
is substantially higher than other display devices. Consequently
high cost of the power supply circuit has been an issue.
Furthermore, the use of a common DC-DC converter requires a large
capacitance capacitor (in the order of micro Farads), resulting in
bringing forth a problem of extreme difficulty in designing the
power supply circuit within a thickness of one millimeter.
[0026] FIG. 2 exemplifies a conventional configuration of a drive
waveform for a passive matrix type device. As shown by FIG. 2, a
pixel located on a selection level line must have drive voltages
applied for the planar and focal conic states, respectively, at the
signal lines in response to the on and off signals, while a pixel
located on a non-selection level line must have a voltage applied
so as not to change a written state at selection. For a
commercially available STN LCD driver LSI, the requirement is five
different voltages for example, bringing forth the problem of a
high cost power supply circuit.
[0027] Next, electric power supplied when driving a noncontact IC
card for example only by the power supplied from an IC card
reader/writer varies a great deal with the distance between the
reader/writer and IC card. This has brought forth a problem of
shortening the communicable distance as compared to common
noncontact IC cards without a display unit or temporary shortage of
power required for the noncontact IC card chip during communication
if the display unit is continuously operated, resulting in unstable
operation. A display control in accordance with power supply is
required for concerned with such a problem.
[0028] Meanwhile, the required power for driving a passive matrix
type cholesteric LC is relatively small except for when starting
up, making it possible to drive it adequately by the power supplied
from a noncontact IC card reader/writer, with a low power output,
equipped with a PDA, et cetera. However, an existing driver LSI
designed for a display of moving pictures has a low impedance
transistor on the last stage and therefore a start-up transition
state will see an extremely large in-rush current (e.g., five to
ten times the steady state). This has lead to the problem of
existing drivers being unable to start up even with a supply of
power several times that of the steady state.
[0029] Preparing a large capacity power supply just for startup is
exceptionally disadvantageous in terms of cost, and besides it is
truly impossible to supply power five to ten times the steady state
by using a reader/writer with a low power output, equipped with a
PDA, et cetera. This makes development of a control method for
starting an existing driver LSI stably with a supply power close to
the power consumption at the steady state vital.
[0030] Furthermore, the cholesteric LC requires two kinds of drive
waveforms with different peak values corresponding to the planar
drive and focal conic drive, respectively, as described above,
additionally the peak values are required to be changed with
temperature. This has then created the problem of a peak value for
the planar drive at high temperatures and that for the focal conic
drive at low temperatures becoming too close to secure a margin for
the peak value when a larger temperature range of operation is
tried. A method for securing a margin for the peak value over a
wide operating temperature range is desired in order to widen the
usable range of the cholesteric LC.
[0031] The next description is of problems of the cholesteric LC
associated with a high-speed drive. As described above, there are
two ways of driving the cholesteric LC, that is, planar drive and
focal conic drive, using an AC pulse voltage in general, in which
writing at higher speed than about a cycle of 20 ms, that is, 20
ms/line, causes an inadequate transition to the focal conic state
as shown by FIG. 3, depending on the material of the LC, leading to
the problem of a large drop in contrast as shown by FIG. 4. While
writing at a lower speed than the above described will gain an
adequate contrast, the time to complete writing a QVGA size (i.e.,
320 by 240 dots) display becomes about 5 seconds for example, thus
causing a problem of making the wait time for completion of display
too long.
[0032] Drive methods have been developed as described below for a
high speed drive method attempting to solve the above described
problems, such methods, however, have been faced with various
problems in application to a wireless drive using a low power
electromagnetic wave, such as a noncontact IC card, which the
present invention aims at. The following lists representative high
speed drive methods and the related problems assuming the use of a
cholesteric LC:
[0033] The patent document 8 listed below has disclosed a writing
method called the FCR (focal conic reset) method which first
applies a reset voltage to all scanning electrodes for a transition
to the focal conic state, followed by applying a selection voltage
sequentially by one scanning electrode at a time. A bulk reset by
selecting all the scanning electrodes, however, requires very large
power consumption due to selecting all the scanning electrodes, and
hence is not suitable to a wireless drive. The power consumption is
particularly large for transition to the focal conic state.
[0034] The patent document 9 also uses a method of full-line
homeotropic reset, requiring very large power consumption as with
the above and precluding use for a wireless drive.
[0035] A DDS (dynamic drive scheme) method disclosed by the patent
document 10, et cetera, while giving a high speed scan, describes a
complex drive wave form which complicates its drive circuit and
hence increases cost. Furthermore, a long elapsed time before the
display state of pixels settles itself (i.e., reset period to
holding period) is so long as to increase the power consumption,
also precluding use for a wireless drive.
[0036] Meanwhile, an MLA (multi-line access) method widely known in
association with a STN drive also drives many lines in bulk,
requiring large power consumption and hence is unsuitable to use
for wireless drive. Furthermore a complicated drive circuit makes
cost high.
[0037] An image with high spatial frequency such as a checkered
pattern makes the power consumption remarkably large, hence drive
methods as described above are all the more unsuitable to a
wireless drive.
[0038] A planar reset leaves a residual image.
[0039] The patent document 11 has disclosed a method for detecting
a plurality of lines including the data the same as writing line
data, for example, and writing the plurality of lines
simultaneously, but a method for determining the maximum number of
lines to be written simultaneously is unknown.
[0040] [Patent document 8] Japanese laid-open patent application
publication No. H11-326871; "Drive method for liquid crystal
display device
[0041] [Patent document 9] Japanese laid-open patent application
publication No. 2002-6287; "Drive method for memory capable
cholesteric liquid crystal display apparatus and its drive
apparatus"
[0042] [Patent document 10] Japanese laid-open patent application
publication No. 2002-55327; "Liquid crystal display apparatus and
drive method for liquid crystal display device"
[0043] [Patent document 11] Japanese laid-open patent application
publication No. H10-20809; "Image display method and apparatus"
[0044] When concerned with a drive associated with a noncontact IC
card for example as with the present invention it does not
particularly require a high speed drive of the order of
microseconds, but rather requires a unique method with a high speed
drive of high quality corresponding to the low power of
wireless.
[0045] Last but not least in this section, let us describe a
problem about a display apparatus using an electronic paper which
utilizes the above described cholesteric LC, et cetera. That is,
while a display apparatus using an electronic paper with a
characteristic of two kinds of properties, i.e., a display will not
disappear soon after cutting off the power and the display content
is discretionarily rewritable, which are well integrated, has been
in development, there has been the problem of such conventional
apparatus not comprising the function of automatic display,
however.
[0046] In other words, such display apparatus lacks the
characteristic of automatic display apparatus as a result of not
possessing information about when, where or how data to be
displayed shall be acquired and/or information about a displaying
form for the acquired display data, and therefore, an automatic
display apparatus, which would acquire display data automatically
based on the information about the acquisition method, or carry out
a display automatically based on information about the displaying
form followed by transitioning itself to a ready state
automatically, has not been provided. Such has been another
problem.
SUMMARY OF THE INVENTION
[0047] A first purpose of the present invention is to provide an
information display system as a whole by enabling mechanical
detachment between an information display apparatus without a power
supply for example and a wireless terminal, which sends
discretionary display data and power thereto.
[0048] The second purpose is to provide a display device capable of
accomplishing a high contrast with a low cost by using a
cholesteric liquid crystal in a plurality of colors and a display
apparatus using such a display device.
[0049] The third purpose is to provide a power supply circuit
capable of operating an IC card stably by using various control
methods, even if the electric power supplied for a noncontact IC
card for example is small.
[0050] The fourth purpose is to provide a device drive method, and
an image display method, with the smallest possible power
consumption in a display apparatus using a cholesteric liquid
crystal for example.
[0051] The fifth purpose is to provide an automatic display
apparatus capable of storing information relating to an acquisition
method for data to be displayed and information relating to a
displaying form for the display data, acquiring external data
automatically, both displaying the data, and subsequently returning
to a ready state automatically, and suitable to a wide range of
applications.
[0052] An information display system according to the present
invention comprises a display apparatus and display data retention
apparatus. The display apparatus comprises a display unit capable
of continuing data display even if the power is cut off, a short
range communication unit for carrying out a short range
communication in order to receive discretionary external data to be
displayed, and a display control unit for controlling display
performed by the display unit in response to received data by the
short range communication unit.
[0053] The display data retention apparatus comprises a storage
unit for holding display data, and a transmission unit for
transmitting display data over to the display apparatus at least
within a short range in response to storage content of the storage
unit.
[0054] A mechanical quick release unit can be comprised for
attaching the display apparatus to the display data retention
apparatus detachably, and data displayed on the display data
retention apparatus, such as a display in a mobile terminal, may be
transmitted to the display apparatus for performing an enlarged
display.
[0055] A display device according to the present invention, in the
display device having two substrates, between which liquid crystal
is injected, comprises partition walls with a structure for keeping
plural colors of liquid crystals, which are injected between the
two substrates, from touching one another.
[0056] Meanwhile, the display apparatus according to the present
invention, comprises a first display device having transmission and
reflection modes, and capable of switching display content, and a
reflective second display device for displaying a fixed image or
character and enabling the viewing of the display content through
the first display device.
[0057] The display apparatus according to the present invention
comprises a temperature compensation unit for changing a peak value
of each drive voltage waveform corresponding to the planar and
focal conic states of cholesteric liquid crystal for example
responding to a temperature. The display apparatus according to the
present invention has a coil furnished for receiving an external
high frequency magnetic field, wherein the coil comprises an
intermediary tap with one end of the coil being grounded and a
for-resonance capacitor being connected between the intermediary
tap and ground, a logic-use power supply unit for supplying
circuits other than the one for display use with a voltage by
rectifying a high frequency voltage generated across the resonating
capacitor, and a display-use power supply unit for supplying a
display-use voltage by rectifying a high frequency voltage
generated between the other end of the coil and intermediary
tap.
[0058] As a device drive method according to the present invention,
in a matrix type display apparatus using a cholesteric liquid
crystal, the device drive method comprises the steps of setting
some scanning electrodes for reset and writing lines to a selection
state and a pause line to a non-selection state, respectively; and
providing a writing data signal to a signal electrode side while
shifting the reset, pause and writing lines respectively.
[0059] Also as a display device drive method according to the
present invention, in the above described matrix type display
apparatus, the drive method comprises the steps of detecting a
plurality of lines on which data patterns to be displayed are the
same from among a plurality of lines on a display screen; and
writing the same pattern in bulk by selecting the detected
plurality of lines simultaneously and applying data of the same
pattern to the signal electrodes.
[0060] A display apparatus according to the present invention
comprises a display unit capable of continuing data display for
example even if power is cut off; a storage unit for storing
information relating to an acquisition method for data to be
displayed and one relating to a displaying form for acquired
display data; and a control unit for controlling acquisition of
display data externally, and display of the display data in the
display unit, both in accordance with the storage content of the
storage unit.
[0061] As described above, according to the present invention, a
display apparatus is configured by using a cholesteric liquid
crystal display device, et cetera, capable of continuing data
display even if the power supply is cut off for instance; and an
information display system is configured by using the display
apparatus, display data retention apparatus, such as a mobile
terminal, for supplying the display apparatus with display data and
power.
BRIEF DESCRIPTION OF THE DRAWINGS
[0062] FIG. 1 exemplifies a conventional configuration of a
cholesteric LC device;
[0063] FIG. 2 exemplifies a conventional configuration of a drive
waveform for a passive matrix type device;
[0064] FIG. 3 shows a problem with a conventional configuration of
a cholesteric LC drive method (part 1);
[0065] FIG. 4 shows a problem with a conventional configuration of
a cholesteric LC drive method (part 2);
[0066] FIG. 5 is a block diagram showing the fundamental comprisal
of an information display system according to the present
invention;
[0067] FIG. 6 is a block diagram showing the fundamental comprisal
of a display apparatus according to the present invention;
[0068] FIG. 7 is a block diagram showing a comprisal of a first
example of an information display system according to a first
embodiment;
[0069] FIG. 8 is a block diagram showing a comprisal of a second
example of an information display system according to the first
embodiment;
[0070] FIG. 9 describes the same screen display mode of the system
shown by FIG. 7;
[0071] FIG. 10 describes a different screen display mode of the
system shown by FIG. 7;
[0072] FIG. 11 describes a screen selection/transmission mode in
the system shown by FIG. 7;
[0073] FIG. 12 describes a data display in a wireless display
panel;
[0074] FIG. 13 describes a mechanical mounting mechanism (part 1)
on the mobile terminal side;
[0075] FIG. 14 describes a mechanical mounting mechanism (part 2)
on the mobile terminal side;
[0076] FIG. 15 describes a mechanical mounting part on the wireless
display panel side (part 1);
[0077] FIG. 16 describes a mechanical mounting part on the wireless
display panel side (part 2);
[0078] FIG. 17 describes a magnet/hook and loop fastener as a
mounting mechanism for the terminal side;
[0079] FIG. 18 describes a magnet/hook and loop fastener as a
mounting mechanism for the wireless display equipment side;
[0080] FIG. 19 exemplifies a wearable display system using a
wireless display panel;
[0081] FIG. 20 describes the planar state of cholesteric LC;
[0082] FIG. 21 describes the focal conic state of cholesteric
LC;
[0083] FIG. 22 exemplifies the reflectance spectrum of cholesteric
LC;
[0084] FIG. 23 describes a planar drive wave form for a cholesteric
LC;
[0085] FIG. 24 describes a focal conic drive wave form for a
cholesteric LC;
[0086] FIG. 25 shows a response characteristic of cholesteric
LC;
[0087] FIG. 26 shows an example comprisal of a reflectance type LCD
device using a cholesteric LC;
[0088] FIG. 27 describes an example of a segment display using a
cholesteric LC;
[0089] FIG. 28 shows an LC separation structure for a matrix
substrate;
[0090] FIG. 29 shows a structure for separating two LCs;
[0091] FIG. 30 exemplifies a comprisal of a pixel in the structure
shown by FIG. 29;
[0092] FIG. 31 describes formation of a sub-dot in the structure
shown by FIG. 29;
[0093] FIG. 32 shows a structure for separating three LCs;
[0094] FIG. 33 describes formation of a dot in the structure shown
by FIG. 32;
[0095] FIG. 34 describes formation of a sub-dot in the structure
shown by FIG. 32;
[0096] FIG. 35 exemplifies an overlapping display of a printed
material with a variable type display device;
[0097] FIG. 36 describes a display state in the configuration shown
by FIG. 35;
[0098] FIG. 37 exemplifies an overlapping display aiming at product
sales;
[0099] FIG. 38 exemplifies an overlapping display for a restaurant
menu;
[0100] FIG. 39 exemplifies an overlapping display for a schedule
chart;
[0101] FIG. 40 exemplifies an overlapping display relating to a
map;
[0102] FIG. 41 exemplifies an overlapping display relating to an
exercise book;
[0103] FIG. 42 exemplifies an overlapping display relating to a
bank loan simulation;
[0104] FIG. 43 exemplifies a power supply circuit for a noncontact
IC card, et cetera, according to a third embodiment;
[0105] FIG. 44 exemplifies a power supply circuit furnished with
independent power supplies for a logic and display uses,
respectively;
[0106] FIG. 45 exemplifies a configuration of a power supply
circuit for an LC driver LSI requiring many different voltage
values;
[0107] FIG. 46 exemplifies a configuration of a circuit for
regulating a power supply to a display unit in accordance with a
supplied electric power;
[0108] FIG. 47 exemplifies a configuration of a clock output
circuit for extending a drive cycle of a display unit in accordance
with supplied electric power;
[0109] FIG. 48 exemplifies a configuration of a circuit for
outputting an image display inhibit signal in accordance with a
supplied electric power;
[0110] FIG. 49 exemplifies a configuration of a current regulation
circuit for a display-use power supply;
[0111] FIG. 50 exemplifies peak values in drive waveforms for a
cholesteric LC;
[0112] FIG. 51 exemplifies peak values in drive waveforms with a
widened pulse width;
[0113] FIG. 52 exemplifies peak values being changed linearly with
temperature in drive waveforms;
[0114] FIG. 53 exemplifies a configuration of a temperature
compensation circuit for accomplishing the characteristic shown by
FIG. 52;
[0115] FIG. 54 is a block diagram exemplifying an LCD device drive
driver according to a fourth embodiment;
[0116] FIG. 55 describes a screen rewriting method according to the
fourth embodiment;
[0117] FIG. 56 is a timing chart for the screen rewriting method
shown by FIG. 55;
[0118] FIG. 57 shows a polarity reversing method for an LC device
drive waveform according to the fourth embodiment;
[0119] FIG. 58 describes an effect of a drive method according to
the fourth embodiment (part 1);
[0120] FIG. 59 describes an effect of a drive method according to
the fourth embodiment (part 2);
[0121] FIG. 60 describes an effect of a drive method according to
the fourth embodiment (part 3);
[0122] FIG. 61 describes a skip drive method as an image writing
method;
[0123] FIG. 62 is a process flow chart of the skip drive
method;
[0124] FIG. 63 shows the result of a first writing in a three-value
writing method;
[0125] FIG. 64 shows the result of a second writing in a
three-value writing method;
[0126] FIG. 65 is a block diagram showing an example comprisal of
an automatic display apparatus according to a fifth embodiment;
[0127] FIG. 66 is an example comprisal of an automatic display
apparatus communicating with a terminal, et cetera, via a wired
connection;
[0128] FIG. 67 is an example comprisal of an automatic display
apparatus wirelessly connected to a terminal, et cetera;
[0129] FIG. 68 is an example comprisal of an automatic display
apparatus equipped with a noncontact IC card interface;
[0130] FIG. 69 exemplifies information about a data acquisition
method and information about a data display form;
[0131] FIG. 70 describes an update date and time display form for
data (part 1);
[0132] FIG. 71 describes an update date and time display form for
data (part 2);
[0133] FIG. 72 describes an automatic display apparatus for
displaying a screen of a terminal, et cetera;
[0134] FIG. 73 describes an automatic display apparatus as a second
display;
[0135] FIG. 74 describes an automatic display apparatus for
displaying advertisement data; and
[0136] FIG. 75 describes an automatic display apparatus for use as
a handout at a conference.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0137] FIG. 5 is a block diagram showing the fundamental comprisal
of an information display system according to the present
invention. In FIG. 5, the information display system comprises a
display apparatus 1 and display data retention apparatus 2.
[0138] The display apparatus 1 comprises a display unit 3 capable
of continuing data display even if the power is cut off for
example, a short range communication unit 4 for carrying out short
range communication in order to receive data to be displayed
provided externally, and a display control unit 5 for controlling
display performed by the display unit 3 in response to
discretionary data received by the short range communication unit
4.
[0139] The display data retention apparatus 2 such as a mobile
terminal comprises a storage unit 6 for holding display data, and a
communication unit 7 for transmitting display data to the side of
display apparatus 1 at least within a short range according to a
storage content of the storage unit 6.
[0140] The display data retention apparatus 2 may further comprise
a long range communication unit, being capable of long range
communication unlike the communication unit 7, for acquiring
display data provided externally so that the communication unit 7
transmits display data acquired by the long range communication
unit to the display apparatus 1 side.
[0141] The display apparatus 1 may further comprise a mechanical
quick release unit for mounting the said apparatus onto a human
body or clothing.
[0142] The display data retention apparatus 2 may further comprise
a display unit with a smaller display area than that of the display
unit 3 comprised by the display apparatus 1 and a mechanical quick
release unit for mounting the display apparatus 1 onto the said
apparatus; or the display data retention apparatus 2 may further
comprise the display unit itself as described above and at the same
time the display apparatus 1 may further comprise a mechanical
quick release unit for mounting the display data retention
apparatus 2 onto the said apparatus.
[0143] Meanwhile, the short range communication unit 4 comprised by
the display apparatus 1 is enabled to receive not only data to be
displayed but also power for displaying and display control
information, all from the display data retention apparatus 2
side.
[0144] A display device according to the present invention
comprises partition walls with a structure for keeping plural
colors of LCs, which are injected between two substrates, from
touching one another.
[0145] A surface of the partition wall facing the substrate may be
configured to possess an adhesive property, the plural colors of
LCs may be cholesteric LCs, or the additive colors of the plural
colors of LCs may be white.
[0146] Meanwhile, the display apparatus according to the present
invention, having transmission and reflection modes, comprises a
first display device capable of switching display contents, and a
reflective second display device for displaying a fixed image or
character and enabling viewing of display content through the first
display device.
[0147] The second display device may be a printed material or a
material written in characters or as an image by hand and
detachably attached to the first display device, or the first
display device may have the function of changing a display area
corresponding to the position and shape of the fixed image or
character on the detachably attached second display device.
[0148] The display apparatus according to the present invention
also comprises a temperature compensation unit for respectively
changing peak values of two kinds of drive voltage waveforms
corresponding to the two stable states of an LC in response to a
temperature.
[0149] The aforementioned LC is a cholesteric LC and the
temperature compensation unit may also be configured to be capable
of changing the peak value of drive wave form applicable to the
focal conic state along the straight line connecting two points,
i.e., the average of the upper and lower limit values of the peak
value of the drive wave form at the lower temperature limit and
that of the upper and lower limit values of the peak value of the
drive wave form at the higher temperature limit.
[0150] The display apparatus according to the present invention has
a coil furnished in order to receive an external high frequency
magnetic field and comprises a display-use power supply unit for
supplying a display-use voltage by rectifying a high frequency
voltage induced by the coil, and a logic-use power supply unit for
supplying circuits other than the one for display use with a
voltage by rectifying a high frequency voltage induced by the
coil.
[0151] In this case, the coil may comprise an intermediary tap with
one end of the coil being grounded, a for-resonance capacitor may
be connected between the intermediary tap and ground, the logic-use
power supply unit may rectify a voltage across the for-resonance
capacitor, and the display-use power supply unit may rectify a
voltage across the other end of the coil and intermediary tap.
[0152] The display apparatus also comprises a display unit for
performing data display by using power supplied externally by
noncontact means, and a display function control unit for
controlling a display function of the display unit in response to
the externally supplied electric power.
[0153] The display apparatus also comprises a display-use power
supply which uses a part of the power supplied externally without a
contact, and a logic-use power supply for supplying circuits other
than the display unit with power by using a part of the power
supplied externally without a contact, and a current regulation
unit for regulating an output current of the display-use power
supply in response to a voltage drop of the logic-use power
supply.
[0154] In the meantime, a display device drive method according to
the present invention, for use in a matrix type display apparatus
using a cholesteric liquid crystal, comprises the steps of setting
some scanning electrodes for a reset and writing lines in a
selection state and for a pause line in a non-selection state,
respectively; and applying a writing data signal to a signal
electrode side while shifting the reset, pause and writing lines,
respectively.
[0155] In this case, a writing alternate signal applied to a reset
and writing lines may reverse polarities within a time
corresponding to one line and also have a period corresponding to
two lines.
[0156] Next, the display device drive method according to the
present invention, for use in the matrix type display apparatus,
also comprises the steps of detecting a plurality of lines, on
which data patterns to be displayed are the same, from among a
plurality of lines on a display screen; and selecting the detected
plurality of lines simultaneously and writing the same pattern data
in bulk by applying data of the same pattern to signal electrodes,
in which the maximum number of the plurality of lines on which a
writing in bulk is carried out may be inversely proportional to the
spatial frequency of the same pattern data.
[0157] Furthermore, the display device drive method according to
the present invention comprises the steps of converting image data
to be written in an LC device into image data having n-number of
gray scales; extracting a pixel of each gray scale level after
conversion; and forming, for the extracted pixels: a sub-image 1
which is formed by converting the pixels on the least bright gray
scale level 1 (i.e., on the black level) and n-th least bright gray
scale level n (i.e., on the white level) into black and white
levels, respectively, a sub-image 2 which is formed by converting
the ones between the least bright gray scale level 1 and the second
least bright gray scale level 2 into a black level followed by
combining with the gray scale level n, and so on and so forth . . .
, and a sub-image (n-1) which is formed by converting the ones
between the least bright gray scale level 1 and (n-1)-th least
bright gray scale level (n-1) into a black level followed by
combination with the gray scale level n, in which a display of the
n-number of gray scales is obtained by starting writing the
sub-image 1, followed by the sub-image 2, and so on and so forth,
and sub-image (n-1) in that order. Also, the display device drive
method comprises the steps of converting image data to be written
in an LC device into image data having n-number of gray scales;
extracting a pixel of each gray scale level after conversion; and
forming, for the extracted pixels: a sub-image 1 which is formed by
converting the pixels on the brightest gray scale level 1 and n-th
least bright gray scale level n into a white and black levels,
respectively,
[0158] a sub-image 2 which is formed by converting the ones between
the brightest gray scale level 1 and the second brightest gray
scale level 2 into a white level followed by combining with the
gray scale level n, and so on and so forth . . . , and a sub-image
(n-1) which is formed by converting the ones between the brightest
gray scale level 1 and (n-1)-th brightest gray scale levels (n-1)
into a white level followed by combining with the gray scale level
n, in which display of the n-number of gray scales is obtained by
starting writing the sub-image 1, followed by the sub-image 2, and
so on and so forth, and sub-image (n-1) in that order.
[0159] FIG. 6 is a block diagram showing the fundamental comprisal
of a display apparatus according to the present invention. In FIG.
6, the display apparatus 10 comprises a display unit 11 for
displaying data; a storage unit 12 for storing information relating
to an acquisition method for data to be displayed and the one
relating to a displaying form of the display data; and a control
unit 13 for controlling acquisition of display data externally in
accordance with storage content of the storage unit 12 and display
of the display data in the display unit 11. The display unit 11 can
be one capable of continuing data display either semi-permanently
or for a certain period of time after the power supply is cut
off.
[0160] In the display apparatus 10 shown by FIG. 6, the control
unit 13 is enabled to start the display apparatus 10 automatically
in response to an instruction either externally or internally
applied, acquire a display data provided externally and transition
the display apparatus 10 back to a ready state after the display is
finished.
[0161] Also, the display apparatus may further comprise a data
acquisition unit for acquiring yet-to-be acquired display data at a
communication restart if a communication is interrupted in the
middle of acquiring display data provided externally, an
overwriting inhibit unit for inhibiting overwriting of data
displayed by the display unit 11, and a nonvolatile storage unit
for storing data for no less than one page of displaying by the
display unit 11.
[0162] Preferred embodiments of the present invention will now be
described by categorizing them into some embodiments in the
following. To begin with, the description will deal with a first
embodiment, that is, an information display system for carrying out
display on the display apparatus side by using power transmitted
from a wireless terminal side, such as a noncontact IC card, along
with data, while an information display apparatus, that is, a
display panel has no power.
[0163] FIG. 7 is a block diagram showing a comprisal of a first
example of such an information display system. In FIG. 7, the
display system comprises a wireless terminal 20 and a wireless
display panel 21. And the wireless terminal 20 comprises an
external wireless transmission/reception unit 23 and is enabled to
exchange external wireless information with a wireless
transmission/reception terminal station 22. The external wireless
transmission/reception unit 23 can be a wireless LAN
transmission/reception unit.
[0164] The wireless terminal 20 comprises a power supply unit 25, a
control unit 26, an antenna 27 for performing short range
communication with the wireless display panel 21 side, a noncontact
transmission/reception unit 28 for controlling communication by
using the antenna 27, a memory unit 29 for storing display data, et
cetera, to be transmitted to the wireless display panel 21, a
display unit drive circuit 30 for controlling a data display over
at the wireless terminal 20, a display unit 31 and a speaker
32.
[0165] The wireless display panel 21 comprises an antenna 36 for
short range communication with the wireless terminal 20, a
transmission/reception unit 37 for carrying out the aforementioned
communication, a control unit 35 for controlling the whole, a
memory unit 38 for storing for-display data and for-control data, a
display unit drive circuit 39 for performing data display, memory
capable display unit 40, and a mechanical mounting mechanism 41 for
enabling the wireless terminal 20 to be detachably attached to the
wireless display panel 21.
[0166] The wireless terminal 20, such as a mobile phone, is usually
furnished with a small display. Use of the wireless display panel
21 as a non-powered display card is for enlarging the screen
display and displaying the whole image in a larger screen, while a
comprisal of the mechanical mounting mechanism 41 as a mechanical
quickly detachable attachment unit for mounting the wireless
display panel 21 onto a mobile phone makes it possible to integrate
it with the mobile phone. In configuring this, installed nearby the
mechanical mounting mechanism 41 is the transmission/reception unit
37 used for short range communication whose system has the
functions of supplying power for a display at the wireless display
panel 21 as well as communication of the display data. This
function enables a short-range wireless communication function such
as an IC card or RF (radio frequency) tag for example.
[0167] The memory capable display unit 40 can take advantage of a
device which for instance retains the display state
semi-permanently even after the power supply is cut off, such as a
later described cholesteric LC, or alternatively a display media
capable of retaining the display state for a certain period of time
if not for semi-permanently, or a display unit in association with
a commonly used buffer memory and its memory content.
[0168] FIG. 8 is a block diagram showing a comprisal of a second
example of an information display system according to the first
embodiment. In FIG. 8, display of image data sent from a digital
camera 43 is performed at the wireless display panel 21. That is,
an image 44 is photographed by an image pickup device 45 and its
data is sent to a wireless display panel 21 by way of the antenna
27 as well as the image 44 being displayed on a rear display panel
46 located on the rear surface of the digital camera 43 via control
by a rear display panel drive circuit 47.
[0169] FIGS. 9 and 10 describe a screen display mode in the
information display system shown by FIG. 7. In FIG. 9, display data
in a wireless terminal 20, that is, that (i.e., a display A) on the
display equipped in a mobile phone, is transmitted over to the
wireless display panel 21 in a state such as the wireless display
panel 21 being mechanically attached to the mobile phone 20 and the
display will be continued even in another state where the wireless
display panel 21 is detached from the mobile phone 20.
[0170] FIG. 10 describes a different screen display mode in which
display data of the wireless terminal 20 and the wireless display
panel 21 are different. That is, the wireless terminal 20 displays
the display A, while the wireless display panel 21 displays the
display B.
[0171] FIG. 11 describes a screen selection/transmission mode in
the information display system shown by FIG. 7. First, the
operation of selecting a screen A to be sent over to the wireless
display panel 21, followed by pressing a transmit button at the
wireless terminal 20, will transmit the data of the selected screen
A over to the wireless display panel 21. In the meantime at the
wireless terminal 20, its display will show "ready for
transmission" prior to data transmission, "a display transmission
in progress" during transmission, and "end display" when completing
a transmission.
[0172] FIG. 12 describes a data display in a non-powered display
card, that is, a wireless display panel conducted comprised by
various terminals including a digital camera. This enables
displaying of display data stored by not only a digital camera but
also a mobile phone or PDA on the non-powered display card. For
example, a mobile phone is able to have the non-powered display
card display data either received from a wireless base station, as
described by FIG. 7, or acquired by way of the Internet.
[0173] FIG. 13 describes the mechanical mounting mechanism 41 as a
mechanical detachable attachment unit connecting the wireless
terminal 20 such as the mobile terminal and wireless display panel,
that is, the non-powered display card. In FIG. 13, the wireless
display panel 21 has a plate spring 50 fixed thereto, which enables
insertion into an insertion part of the mobile terminal and fixing.
The plate spring 50 can also be fixed onto the insertion part of
the mobile terminal and a mechanical reinforcement plate can also
be installed over the wireless display panel 21. Since the
connecting part is not used for an electrical connection physical
damage to some extent caused by friction or the like is therefore
not a problem. A magnet coil 51, equivalent to the antenna 27 used
for short range communication as described in FIG. 7 for example,
can be installed nearby the mounting part.
[0174] FIG. 14 shows an alternative configuration, which employs
coil springs 52 and 53 in place of the plate spring 50 shown by
FIG. 13, enabling a mechanical mounting by inserting the wireless
display panel 21 between these springs.
[0175] FIGS. 15 and 16 describe a mechanical mounting part on the
wireless display panel 21, that is, on the non-powered display card
side. Two mounting parts 54 are equipped in the card to allow a
vertical or horizontal mounting, with FIG. 15 showing a displaying
state for the vertical mounting. A coil corresponding to the
antenna 36 shown by FIG. 7 is comprised nearby the two mounting
parts, and drivers 55 used for displaying and ICs 56 used for
control are comprised in the card. FIG. 16 shows a display state of
mounting the wireless display panel 21, that is, the non-powered
display card horizontally.
[0176] FIGS. 17 and 18 exemplify a mechanical mounting mechanism
different from the configurations shown by FIGS. 13 through 16.
Here, a magnet/hook and loop fastener 57 is used as a mounting
mechanism, with FIG. 17 showing a state of mounting a non-powered
display card onto the wireless terminal (e.g., mobile terminal) 20.
FIG. 18 shows the non-powered display card being detached from the
wireless terminal 20, also showing magnet/hook and loop fastener 57
being used in place of the mounting part 54 shown by FIG. 15.
[0177] FIG. 19 exemplifies a wearable display system mounting the
wireless display panel 21 onto clothing for example. It is possible
to carry out a screen display on a display card mounted onto a
person at a necessary instance in a style such as fixing a hook and
loop fastener 58 on the back side of the wireless display panel 21,
that is, the non-powered display card, or by wrapping the display
card itself around an arm so as to hold the wireless terminal 20
close to the display card.
[0178] For example, mounting a display card on an arm, listening to
a voice by holding a mobile phone close to an ear and bringing the
arm close to the mobile phone make it possible to have a phone
conversation while looking at the screen display on the card. By
this method it is possible to take advantage of a large screen
display of lightweight and compact size, et cetera, without any
need of a battery due to non-powered card. Furthermore, it is
possible to leave a mobile phone in a breast pocket and bring a
display card close to the chest to have the display card detected
and thereby carry out data transmission and the resultant screen
display.
[0179] Note here that the display of a still image is preferred for
the one on the wireless display panel 21, that is, the non-powered
display card. The reasons are that a device capable of continuing
the display after the power is cut off for example has a property
of low writing speed to begin with, that a large display screen is
often used for a still image, taking advantage of its large
information capacity, and that displaying moving images on a screen
with a large information capacity requires very large power
consumption. Moreover, generally speaking, transmission of a
display to a non-powered display card should preferably be
conducted intermittently in order to minimize the power
consumption. For example, transmission and display of data in 50 ms
followed by a pause of 100 sec greatly saves display power.
[0180] Note also here that in claims of the present invention, a
display unit corresponds to the memory capable display unit 40, a
short range communication unit corresponds to the antenna 36 and
transmission/reception unit 37, a display control unit corresponds
to the control unit 35 and display unit drive circuit 39, a storage
unit corresponds to the memory unit 29, and a communication unit
corresponds to the antenna 27 and non-contact
transmission/reception unit 28, all of the above relating to claim
1, with all the aforementioned numbered components being listed by
FIG. 7.
[0181] In the claim 2, a long-range communication unit corresponds
to the external wireless transmission/reception unit 23. In the
claim 3, a mechanical detachable attachment unit corresponds to the
mechanical mounting mechanism 41; and in the claim 4, a display
unit corresponds to the display unit 31, with all the numbered
components above being listed by FIG. 7, and a mechanical
detachable attachment unit corresponds to the mounting part 50
shown by FIG. 13 for instance.
[0182] As described so far, the first embodiment enables the
displaying of a screen furnished with mobile equipment by a large
screen or multi-screens in hands-free and also the use of display
results of the remaining display through the utilization of a
memory function even after detaching the large screen from the
mobile equipment by mounting a non-powered large screen display,
which is usually separated from a mobile equipment, et cetera,
integrally with a mobile terminal or a mobile equipment such as a
digital camera at the time of usage.
[0183] Specifically, the use of a cholesteric LCD device allows
acquisition of a low cost and easy-to-make film based, passively
driven, high resolution, memory capable color display. It is
possible to accomplish not only the same resultant effect as
printing by a mobile printer without ever using one, but also a
color display or large screen display which is hardly achievable by
a mobile printer. Especially for a terminal required to be of
compact design such as a mobile phone, the actual effect of a large
screen display is substantial.
[0184] It is also possible to obtain reference materials, catalog
information, et cetera, by using the wireless communication
function comprised by a mobile terminal to store it as a display
record for a large screen display. Holding a display panel with a
memory capable display function in a pocket or brief case enables
instantaneous easy viewing of a large screen. Also, mounting a
non-powered display card onto a person makes it possible to solve
the conventional shortcomings of weight, bulkiness and need to
recharge, et cetera, caused by a wearable display using a
battery.
[0185] What follows here is the description of a cholesteric LCD
device as a representative display medium capable of continuing
display in a state of the power supply being cut off and a display
apparatus using the display device as a second embodiment of the
present invention.
[0186] First, let a characteristic of the cholesteric LC be
described in general terms. The cholesteric LC has a property of
reflecting light in a certain wavelength range selectively; among
such materials chiral-nematic LC is the result of nematic LC
forming a cholesteric phase by adding a chiral material thereto.
The cholesteric LC provides two stable states, i.e., the planar
state as a reflective state and the focal conic state as a
transmissive state, by electrical control, having the
characteristic of memory property in holding the planar and focal
conic states, respectively, semi-permanently unless a certain kind
of external force is applied.
[0187] FIGS. 20 and 21 describe the planar state and the focal
conic state, respectively, of cholesteric LC. In a display
apparatus using a cholesteric LC, control of the two states is
carried out by switching the orientation states of the liquid
crystal molecules. FIG. 20 shows the planar state in which light in
a specific wavelength range is selectively reflected. In this
planar state, circularly polarized light propagating along a
helical path with a pitch and rotation direction the same as the
helix of the liquid crystal molecules is selectively reflected. A
wavelength .lamda. at which the reflection becomes a maximum is
given by the following expression, where "n" is the average
refractive index, and "p" is the helical pitch, of the LC:
.lamda.=n*p
[0188] The reflectance band .DELTA..lamda. increases with a
refraction index anisotropy .DELTA.n of the LC.
[0189] FIG. 21 shows the focal conic state in which most of the
incident light is transmitted through, hence the LC becomes
transparent. Therefore, installing a layer with a discretionary
color under the LC layer makes it possible to display the color in
the focal conic state. Accordingly, installing a light absorption
layer (black) under the LC layer, with the wavelength band of
reflecting light in the planar state being about 550 nm, will make
it possible to obtain a green mono-color display with a black
background.
[0190] FIG. 22 exemplifies a reflectance spectrum of cholesteric
LC. The coexistence of a plurality of LC elements (i.e., blue,
green and red) with different reflectance bands will basically
enable full color display. The reflectance ratio is close to 50%
due to reflection of either the left or right circularly polarized
light.
[0191] FIGS. 23 and 24 describe a common drive waveform for the
cholesteric LC, for which a drive is carried out by applying a
pulse voltage. An application of a strong electric field untangles
the helical structure of the LC molecules so that all the molecules
orient themselves in the direction of the electric field, i.e., a
homeotropic state.
[0192] In FIG. 23, applying a pulse of .+-.40 volts, for example,
followed by removing the electrical field forms a helical structure
in which the helical axis of LC molecules align themselves vertical
to the electrode, thereby assuming the planar state to reflect
light selectively corresponding to the helical pitch.
[0193] In FIG. 24, applying a pulse of .+-.24 volts, for example,
followed by removing the electrical field, that is, applying a weak
electrical field so as not to untangle the helical axis of the LC
molecules completely, followed by removing the electrical field
makes the helical axis of the LC parallel with the electrode,
obtains the focal conic state, transmitting the incident light.
Contrarily, applying an intermediate strength of electrical field
followed by removing it will obtain a state in which both the
planar and focal conic states coexist, enabling an intermediate
halftone display.
[0194] FIG. 25 shows a summary response characteristic of
cholesteric LC. In FIG. 25, V.sub.F0 is the threshold voltage for
starting a transition to the focal conic state, between V.sub.F100a
and V.sub.F100b is the voltage range for a completely focal conic
state, V.sub.P0 is the threshold voltage for starting a transition
to the planar state and V.sub.P100 is the threshold voltage for
assuming a completely planar state. If the initial state is the
planar state, increasing the pulse voltage gives rise to a drive
band for a transition into the focal conic state up to a certain
limit, and further increasing the pulse voltages will make the
drive band for a transition into the planar state again. If the
initial state is the focal conic state, increasing the pulse
voltage gives rise to a drive band for a gradual transition into
the planar state.
[0195] FIG. 26 shows an example comprisal of a reflectance type LCD
element using a cholesteric LC. In FIG. 26, inserted between
substrates 60 are ITO (indium tin oxide) electrodes 61, a display
layer 62 and a light absorption layer 63, the display layer 62 that
is the LC layer, is sealed at both ends by the sealant 64.
[0196] FIG. 27 describes an example of a segment display using the
cholesteric LC. For example, in the display of the last digit "3",
driving to make the segments (2) and (5) assume the focal conic
state, and the other segments (1), (3), (4), (6) and (7) assume the
planar state, thereby displaying the number 3.
[0197] The next description is of a comprisal of a display device
using cholesteric LC. A cholesteric LC basically indicates a
monochrome color of a certain color tone and, if two LCs mix, they
end up mingling easily, resulting in an inability to reflect a
desired color tone. That is, a mixture of two or more LCs makes
either an intermediary color or a non-reflective state. Therefore,
it is necessary to set up partition walls in a pair of facing
matrix substrates so as to make a structure isolating adjacent
pixels or in the unit of dots in order to keep a plurality of LCs
from mixing with one another and inject the respective LCs from
different inlets.
[0198] Although a capsule structure, to contain an LC in a capsule
is being used as a method for separating LCs, the influences of the
borders between capsules and thickness thereof bring forth a
reduced contrast by optical noise and an increase in drive voltage,
making them disadvantageous for a display apparatus. It is also
very difficult to place desired capsules in desired pixels, whereas
it is possible to accomplish a high contrast at a low cost by
adopting a separation structure using partition walls as in the
second embodiment.
[0199] FIG. 28 shows an LC separation structure for a matrix
substrate which is applicable to both a passive type simple matrix
substrate and an active type matrix substrate for TFT, et cetera.
In the second embodiment, a separation structure for inserting two
LCs is exemplified by taking a passive type simple matrix substrate
as an example. A partition wall 62 is featured for each line of
electrodes 61 on the lower side of the substrate 60 in order to
insert two LCs in adjacent dots. The opposing upper substrate 60
has electrodes perpendicular to those of the lower substrate 60,
hence accomplishing a matrix drive. The partition walls 62 are made
of a resin, which is not dissolved by the LC and are formed by
photo lithography. While the partition walls 62 can be pressed
against opposing substrates by keeping the inside of the cells
depressurized, it is desirable to improve the durability by giving
an adhesive property to the partition wall material to fix the
opposing electrodes firmly. Since the partition walls are made of a
resin, it is therefore possible to adhere them to the opposing
electrodes by pressing or heat processing.
[0200] FIG. 29 shows a structure for separating two LCs 63 and 64,
providing two inlets for avoiding mixing of LCs. A common filling
method for a LC is to immerse it in an LC tank under vacuum
conditions, followed by returning it to atmospheric pressure to
complete the filling. This requires that two inlets must be formed
on different edges of empty LC cells. The filling procedure is to,
fill one LC, and seal it with a sealant 65, followed by filling the
other LC. As shown by FIG. 29, it is possible to fill a different
LC for each adjacent electrode line. It is then possible to display
a full color and additive mixture of colors.
[0201] FIG. 30 exemplifies a comprisal of a pixel in the case of
using two LCs 63 and 64 as shown by FIG. 29. As a display of white
and black is desired by a display device, the two LCs here are
complementary colors so that white can be made by the additive
mixture of colors. For example, making orange and blue colors the
reflected light of the respective cholesteric LCs will produce
white. In FIG. 30, two dots 66 (i.e., sub-pixels) of orange and
blue colors form a pixel 67. While reflected light of a cholesteric
LC can be made an intermediate reflectance ratio by adjusting the
applied voltage, thereby achieving a halftone display, the stable
drive method is that of a binary display (i.e., the maximum and
minimum reflectance) which can allow a wider tolerance of contrast
against differences in thickness of the LC and precision of drive
conditions of the two LCs. Incidentally, division of the LC in the
transverse direction corresponding to the pixel 67 applies to
one-line driving unit of the electrode 61 featured on the upper
substrate 60 for the configuration shown by FIG. 28.
[0202] Accordingly as shown by FIG. 31, a further division of a dot
makes sub-dots 68 which will, individually driven enable a halftone
display. There are four colors, i.e., white, black, orange and
blue, available in FIG. 30, whereas a nine-color display is now
enabled by the configuration shown by FIG. 31.
[0203] Furthermore in FIGS. 30 and 31, it is possible to display by
driving the respective dots or sub-dots by the smallest drivable
minimum unit as virtual pixel units. Without specific processing, a
high-resolution image is formed, but either an orange or bluish
color unevenness may be formed as a result of continuous dots of
either color depending on the image. It is then possible to display
a high resolution black and white image by image processing such
that the number of each lighting color becomes approximately the
same within an area in the range of several square millimeters,
when displaying an image. For example, if the orange color appears
continuously, dots nearby the orange dots will be replaced by a
blue dot(s). This method regards a dot as a virtual pixel, thereby
enabling a conversion to a high-resolution display mode in black
and white display mode.
[0204] FIG. 32 shows an embodiment using three LCs, 69, 70 and 71.
This exemplifies cholesteric LCs displaying by reflection three
primary colors, R, G and B (red, green and blue, respectively). It
used to be very difficult to insert three kinds of LCs separately
in a substrate on one plane, but this inventor has discovered the
possibility of inserting three kinds of LCs in a substrate on one
plane in order to accomplish a dot array shown by FIG. 32 if a line
structure is made up of a dot array having a cycle of "X, Y, Z, Z,
Y, X" where one LC (Y) 70 is inserted between the other two LCs (Z)
69 and (X) 71 alternately. Such a dot array is laid out by two
kinds of pixels made up of one pixel of RGB and one pixel of BGR
(in the respective orders). The resolution of G is high in terms of
human perception and accordingly G-dots are arrayed in
equidistance, while the colors R and B are low in the perceptive
resolution, causing little problem if they are not arrayed in
equidistance. Inlets are placed on the respectively different edges
for avoiding a mixture of different color LCs.
[0205] FIGS. 33 and 34 show examples accomplishing a high
resolution and halftone displays by further dividing dots to form
sub-dots 68. Assuming a binary display as in the case of FIG. 30,
the configuration of FIG. 33 enables an eight-color display, while
the FIG. 34 enables a 64-color display. Moreover in FIGS. 33 and
34, if the minimum drivable unit of respective dots or sub-dots is
driven for display as a virtual pixel unit, a high-resolution image
is formed as in the case of FIGS. 30 and 31. Through image
processing, a conversion to a black and white high-resolution
display mode will be enabled.
[0206] The next description is of a display apparatus combining a
display device using a cholesteric LC with a printed media using
paper and/or a photograph. As described before, a cholesteric LC
has two stable states, i.e., a planar state as a selective
reflective state and a focal conic state as a substantially
transparent state. A common display type has provided a bright
display in the reflective state and a dark display in the
transmissive state by placing a light absorption layer (i.e., black
layer) under the LC element.
[0207] The cholesteric LC, however, allows a transparent state,
that is, vision of a background in the focal conic state if a light
absorption layer is not placed thereunder. Accordingly, utilization
of the transparent state in the focal conic state and integration
with a printed medium, e.g., generally a paper medium, enables a
provision of an LCD apparatus capable of a wide application.
[0208] There have been proposals for restaurant menus, et cetera,
as application examples for an electronic paper capable of a
semi-permanent display, but where there is no need to change the
display of the entire menu area. An image of merchandize for
example can usually be a fixed display, while it is desirable to
use a photograph for improving the image. The accompanying price
and advertisement of "today's special" for example should
preferably be a variable display. Accordingly, the second
embodiment is configured to accomplish an overlapping display form
as a whole by combining an electronic paper media, such as a
display device using a cholesteric LC, with a printed medium such
as a photograph. An image of merchandize as printed material has a
high degree of reality, while the price or advertisement content of
today's special can be changed by using electronic paper, thus
enabling an integration of paper and electronic paper.
[0209] It is possible to accomplish a display suitable to the
display content of the printed material by adopting for example a
matrix display type for the electronic paper, which uses a
cholesteric LC. Diverse application forms can be conceived by
making printed materials as templates. For example, a use of a
calendar as a printed material accomplishes a variable schedule
chart by an overlapping display of the electronic paper with the
calendar.
[0210] FIG. 35 exemplifies an overlapping display of a printed
material (e.g., photo) with a variable type display device using a
cholesteric LC, overlapping a variable display device 75 on the
surface of a printed material 74. The variable type display device
is not formed with a light absorption layer. FIG. 36 describes a
display state, showing a transmission mode (in the focal conic
state), on the left part of the drawing, and reflection mode (in
the planar state), on the right, of the variable display device 75
placed above the printed material 74. As incident light 77,
illumination light, illuminates the display device, the light
illuminates the printed material as it is in the transmission mode
(shown on the left), the reflected light 78 is reflected according
to the image of the printed material, and is thereby visible
through the display device in the transmission mode. That is, the
printed material is visible as is. In the reflection mode (shown on
the right), light of wavelength according to the layer pitch of the
cholesteric LC is reflected thereby while light of other
wavelengths is transmitted through the LC to illuminate the printed
material. The reflected light in accordance with the image of the
printed material is reflected thereby, and hence transmitted
through the LC in the reflection mode. This causes reflected light
79 reflected off the LC to overlap with the reflected light 78
reflected off the printed material, thus becoming the display light
80. This is how an integration of the printed material on a paper
media with a good image quality with the display device of a
variable display medium is achieved.
[0211] The LCD displays color in accordance with its layer pitch.
This sometimes causes a reduced visibility of the printed material
laid underneath, depending on the color thereof, requiring a
consideration of the area for carrying out a variable display.
Black is preferred for the area of printed material in order to
improve the visibility by increased contrast. Also, the use of gray
for reducing reflections will enable better visibility.
Alternatively, coloring the area for changing the reflected light
78 to a specific color will make an additive color with the display
device reflected light 79, thereby enabling a change of color. For
example, setting the reflected light 79 of a display device to
orange and the color of printed material to blue will make the
displayed color white. Through various refinements of printed
material, various colors can be given to each area. White is the
most favored color. Setting the colors of printed material and
reflected light of the display device with the relation of
complementary colors with each other accomplishes a white display.
Orange and blue are complementary.
[0212] FIG. 37 exemplifies a display aiming at product sales such
as a menu or a catalogue. A product image uses a printed material
with a good display quality. For a restaurant for example, print an
image that looks delicious to use as a fixed display. For other
display, particularly for character display, use a variable display
device. The printed part placed on the lower layer of the variable
display device 75 uses a printing pattern, with good visibility,
such as black. Such character displays can assume various displays
such as price, discount merchandize, lunch menu for the day,
information about store hours, banner ad. An online variation of
display on the variable display device will bring about various
applications, enabling customer-oriented custom menus including a
limited time only price, inventory adjustment, change of today's
specials, customer oriented ad display, group discount, discount
for female customers, family discount display, discount for member,
discount for sponsor points. An in situ enlarged display for
elderly people is also possible. Product images use high quality
realistic images.
[0213] FIG. 38 exemplifies a restaurant menu, setting variable
display areas below the respective images for displaying the
prices. FIG. 38 describes printed parts and variable display parts
separately. A change of images, such as by replacing the
merchandize, can be achieved by replacing the printed material. The
present embodiment is configured to allow easy attachment and
detachment of printed materials. The variable display, utilizing a
matrix type display device, is well suited to layout changes of the
printed materials.
[0214] FIG. 39 exemplifies a schedule chart achieved by replacing
the printed material shown by FIGS. 37 and 38 with a calendar. The
printed material is a calendar. A schedule is written in the
variable display online. If online, a change in schedule can be
entered at any time and it is easily possible to view the schedules
of a plurality of personnel. A change in schedule can be reflected
instantly. A common format and information sharing are enabled,
realizing effective management. A change of months merely requires
a replacement of the printed material, instantly becoming anew
schedule chart. A hand written entry into the printed schedule, if
required, is possible by easily detaching, annotating and
re-attaching the printed calendar. The variable display device,
being a matrix display device as with FIGS. 35 through 38, allows
for an easy change of layout reflecting the printed material. A
certain pattern is printed on the printed material in consideration
of the display areas. The schedule display part is printed by a
certain pattern for giving good visibility such as black, gray or a
complementary color.
[0215] FIG. 40 exemplifies an application to a map display whose
structure is the same as FIG. 39, et cetera. The printed material
is a layout chart including a road map, site map, plan view of
premises, while the variable display unit is capable of displaying
the current position (e.g., "you are here"), destination (e.g.,
"your destination"), passage history, et cetera. It is also
possible to display an advertisement in association with the
destination. Estimated times of arrival at transit points, which is
only possible online, can be displayed as well. A large change in
destinations can be displayed by an easy replacement of the
applicable maps. A use of such a display apparatus makes a
remarkably convenient guide substrate. FIG. 40 exemplifies a site
map. A distribution by changing printed materials specific for the
customer/visitor is enabled. An equipping wireless display system
will enable a display of the current position every time the bearer
passes the respective gates. Useful information nearby the current
position can also be displayed.
[0216] FIG. 41 exemplifies an application to a reference book or
workbook. Exercise problems are printed on the printed material and
the solutions and description will be displayed later. This gives a
chance to read the solutions and description on the spot, providing
a better understanding. A change of problems merely requires a
replacement of the printed material. FIG. 41 exemplifies an
exercise book. Unlike a personal computer (PC) monitor, a
reflective display apparatus causes much less fatigue, helping an
effective understanding.
[0217] FIG. 42 shows an example application to a display for
simulation used by a financial institution such as a bank or
insurance company. Common items are printed on the printed material
and customer data for the customer will be displayed online.
Availability of simulation results on the spot allows a simple
explanation for the customer. A change of products merely requires
an easy replacement of the printed materials. FIG. 42 exemplifies
an application to a bank loan simulation. An insurance sales
representative sometimes visits a customer carrying a laptop PC.
Occasional explanation by using a PC display is hard to visualize
especially for the customer for who it is hard to understand. A use
of the display apparatus according to the present second embodiment
provides good visibility, helping the customer understand the
explanation easily.
[0218] As described so far, the second embodiment enables
accomplishment of multi-color display by injecting a plurality of
color LCs in a matrix display device using a cholesteric LC. The
use of simplified components having a reduced number of border
surfaces and a high contrast makes it possible to accomplish a cost
reduction.
[0219] Also, the combination of a cholesteric LC matrix display
device, as a variable display device, with a printed material, as a
fixed display device, integrates an electronic paper with paper,
making it possible to bring out the characteristics of the
electronic paper and paper to the largest extent. Making printed
material as a template and only replacing content thereof with new
content by detaching from, and attaching to, the variable display
device enables the development of various applications. A database
storing the templates for printing materials enables layout change,
content change and update of the display device instantly. The
variable display device is durable enough for many times of use,
hence reducing cost. The fixed display device may be hand-written,
in place of printed material, and an overlapping display is also
possible by placing a cholesteric liquid crystal display device on
a picture painted on a wall of building.
[0220] The next description is of a third embodiment. In using a
non-powered display card as described in the first embodiment for
accomplishing a semi-permanent data display for example in the
present embodiment, various control methods are required for a
power supply circuit since electric power supplied from a
noncontact IC card reader/writer for example is small. Such a
control for the power supply circuit is described as the third
embodiment.
[0221] As described in relation to FIGS. 23 and 24, two kinds of
voltage values are required to drive the cholesteric LC for the
planar and focal conic states respectively. Moreover, the drive
voltage for the planar drive is approximately 40 volts,
substantially higher than that of other display devices. A use of a
common DC/DC converter for example will require a large capacitance
capacitor of micro farad order, making it extremely difficult to
limit the thickness of a power supply circuit to within about 1 mm,
that is, the thickness of a non-powered display card.
[0222] Accordingly, the third embodiment is configured to use a
power supply circuit for generating a high voltage of about 40
volts by an ultra-thin circuit through utilizing a high frequency
magnetic field used to supply a signal and power for a noncontact
IC card or RF tag, instead of using a DC/DC converter.
[0223] FIG. 43 exemplifies such a power supply circuit, which works
as the power supply for display such as power for logic use by an
LCD driver and the power supply for the display device per se, that
is, for display power required by the cholesteric LC.
[0224] The configuration shown by FIG. 43 provides an intermediate
tap T in a coil which, having an inductance L, produces a voltage
induced by a high frequency magnetic field from a noncontact IC
card for example, grounds one end of the coil, connects a capacitor
C1 for resonance between the intermediary tap T and the ground,
supplies a voltage for logic by way of a half-wave rectifier, and
supplies a voltage for display through a half-wave rectification,
instead of connecting a capacitor for resonance between the other
end of the coil and the intermediary tap T. As described,
connection of a capacitor for resonance between an intermediary tap
for extracting a voltage for logic and the ground enables variance
in production to be minimized and a supply of stable DC
current.
[0225] FIG. 44 exemplifies a power supply circuit furnished with
independent power supplies for logic and display uses,
respectively, in place of installing an intermediary tap as with
the configuration shown by FIG. 43. The upper part of FIG. 44 is a
power supply circuit for logic, which can be considered to make the
lower part of FIG. 43 independent. In a common noncontact IC card,
the value of L1 for receiving power is 1.4 .mu.H for example, and,
by using C1 of 100 .mu.F for example, a voltage for logic use of 5
volts can be obtained. Although the use of a DC/DC converter will
obtain a display-use power supply voltage by stepping up the
aforementioned voltage, a large capacitor of the .mu.F order will
be required as described before. Accordingly, a use of
approximately L2=4 to 5 .mu.H, for example, obtains the display-use
voltage.
[0226] Next, a passive matrix drive circuit for example requires
the application of voltages to LC cells on the selected level
scanning line for the planar and focal conic drives, respectively,
while a voltage to LC cells on the unselected level scanning line
so as to keep a state of writing at selection independent of the
segment line level. That is, the applied voltage is to suppress a
common cross talk, thus requiring five kinds of voltage values in
the application of commercially available STN LCD driver LSI for
example.
[0227] FIG. 45 exemplifies a configuration of power supply circuit
for such a case. The power supply circuit for logic use is the same
as in the case of FIG. 44, whereas that for display use utilizes a
circuit with a power supply circuit applying double voltage
rectification being connected serially in multiple stages, in place
of the power supply circuit shown by the lower part of FIG. 44. It
is possible to supply five different voltages for example by taking
out voltages from suitable parts in accordance with the required
voltages. Both half wave and full wave rectifier circuits can be
applied to the rectifier circuit. Incidentally, if there is a need
to prevent an over-voltage in the circuits shown by FIGS. 43
through 45, the insertion of a Zener diode in parallel between a
voltage output terminal and the ground will be able to improve a
reliability of the power supply. Note also that the coils L2 and L4
are wound in the same direction while the coils L3 and L5 are wound
in the reverse direction to the aforementioned two coils of the
four coils as shown in FIG. 45. This is because a result of
experiments has revealed that such coils wound in different
directions provide a higher voltage.
[0228] Next, when using a noncontact IC card for example as a
non-powered display card, the supplied electric power from a
noncontact IC card reader/writer varies greatly depending on the
type thereof, the distance between the noncontact IC card
reader/writer and the noncontact IC card. This may bring forth the
possibility of shortening a communicable distance substantially as
compared to that of a common noncontact IC card without a display
unit, or the operation becoming unstable due to power shortage
during communication, if the display unit on the card is operated
continuously. The third embodiment accordingly limits a display
function in response to supplied electric power as a countermeasure
to the above-described problem.
[0229] FIG. 46 exemplifies a configuration of a circuit for
completely shutting off a power supply to a display unit according
to a display-use power supply input voltage value in response to a
supplied electric power from a reader/writer for example. In FIG.
46, a comparator (CMP1) compares a voltage from VR1, which is a
result of dividing a display-use power supply input voltage, with a
reference voltage and if the display-use power supply input voltage
is higher, an output of the CMP 1 becomes a high (H). A circuit
comprising a TR1, TR2 and R1 is a common current limiter circuit by
which a display-use power supply output is supplied if an output of
the CMP1 is H, whereas the display-use power supply output is
completely shut off if the output of the CMP1 is low (L). By
setting the reference voltage appropriately, the power supply to
the display unit is totally shut off by utilizing the current
limiter circuit if the power supply amount, that is, the
display-use power supply input voltage is barely at the required
value even though the noncontact IC card chip operates.
[0230] FIG. 47 exemplifies a configuration of a clock output
circuit for extending an average drive cycle of a display unit in
accordance with a supplied electric power to a noncontact IC card
for example. This circuit extends an average clock cycle in
accordance with the supplied electric power to delay the drive
cycle of the display unit if the supplied electric power is
sufficiently larger than the minimum value required by the
noncontact IC card chip, that is, the required value for operation
and yet smaller than the average required value for operating the
display unit as well in the steady state.
[0231] In FIG. 47, if the display-use power supply voltage value
divided by VR2 is small, the output of CMP2 becomes L, hence
stopping clock output as an output of the gate AND1. For example,
in the display-use power supply circuit described in FIG. 44, the
clock output resumes as a result of the clock being stopped to shut
off the electric power supply, followed by charging the capacitor
C3 to recover a display-use power supply voltage. A repetition of
such cycles extends the clock cycles, that is, delays the average
drive cycle of the display unit.
[0232] FIG. 48 exemplifies a configuration of a circuit for
outputting an image display inhibit signal in order to make the
display unit display character data only and not image data in
accordance with supplied electric power. This circuit is to display
character data only and not image data, thus limiting a display
function, if a supplied electric power is larger than the minimum
value required by the noncontact IC card chip and yet much smaller
than the average required value for operating the display unit as
well in the steady state. In FIG. 48, if the display-use power
supply voltage value divided by VR3 is smaller than a reference
voltage, the output of CMP3 becomes H, thereby outputting an image
display inhibit signal.
[0233] The next description is of current limiting for a
display-use power supply. It is possible to drive a passive matrix
type cholesteric LCD panel by an existing driver LSI used for a
passive matrix type STN LCD by using the above described power
supply circuit. Power supplied from a noncontact IC card
reader/writer having a very small output power can operate the
aforementioned passive matrix type cholesteric LCD panel, except
for when starting up. Such an existing driver LSI, however,
assuming use for displaying a moving picture, has a transistor on
the last stage with a low conductive impedance so as to allow an
extremely large surge current (i.e., a magnitude of five to ten
times the steady state) in a transition state at the start. Due to
this, it may not be possible to start an existing driver LSI even
with a current several times the steady operation state.
[0234] But, preparing a large power supply just for starting is
tremendously disadvantageous in terms of cost. Besides, it is just
impossible to supply electric power of the magnitude of five to ten
times the steady state operation by way of an existing noncontact
IC card reader/writer having a very small output power. Accordingly
the third embodiment is configured to limit the current for a
display-use power supply in order to start up an existing driver
LSI stably by supplying power as close to the power consumption in
the steady state as possible.
[0235] FIG. 49 exemplifies a configuration of a current regulation
circuit for a display-use power supply. In FIG. 49, current
regulation for the display-use power supply is carried out if a
voltage drop value of a logic power supply drops more than five
percent, for example, of the nominal value by setting up the value
of VR1 so as to carry out the current regulation when the logic
power supply voltage assumes a prescribed value or less.
[0236] Meanwhile, at startup, stopping clock output until the
voltage value of the display-use power supply exceeds a prescribed
value by using the same circuit as FIG. 47 enables a stable and
quick startup of the existing driver LSI, since the display-use
power supply voltage generally increases with time monotonically.
In this case differ from explanation of FIG. 47, just because the
display-use power supply voltage increases monotonically, the clock
will be stopped until the aforementioned value exceeds a prescribed
value, e.g., 95% of the standard value.
[0237] In an existing common LCD driver LSI, a display-use power
supply current may sometimes exceed the average current for the
steady state operation depending greatly on the display pattern,
not just at the startup. An interruption of display panel drive
until the display-use power supply voltage recovers to a prescribed
value by regulating the current as with the startup will enable
stable operation of the existing driver LSI.
[0238] The next description is of temperature compensation of the
drive characteristic for the cholesteric LC according to the third
embodiment. The cholesteric LC requires two drive waveforms with
different peak values corresponding to the planar and focal conic
states, in which the peak values further changes with temperature.
Consequently, a temperature compensation for changing a peak value
corresponding to temperature is necessary for widening an operating
temperature range. The third embodiment is configured to secure a
margin of peak values in a wide operating temperature range by
changing the peak value of the drive waveform linearly with
temperature.
[0239] FIG. 50 exemplifies peak values in the planar and focal
conic drive waveforms for a cholesteric LC in the case of a 10 ms
pulse width. Because a peak value of a certain level or higher
invariably transitions to the planar state, a peak value for the
planar state is expressed by one curve corresponding to the minimum
value therefor. Vis-a-vis the above, because a transition to the
focal conic state occurs within a certain voltage range of peak
values, a peak value for the focal conic drive is expressed by two
curves corresponding to the lower and upper limits, respectively,
therefor.
[0240] Referring to FIG. 50, the margin of peak value for driving
to the focal conic state is narrow across the temperature range
because the peak values corresponding thereto change with
temperature greatly.
[0241] Compared to the above, it is known that the margin of peak
values for the focal conic drive becomes wider with pulse width.
FIG. 51 exemplifies peak values for the planar and focal conic
drives in the case of a 50 ms pulse width. The margin of peak value
becomes several times wider as compared with the case of the 10 ms
pulse width shown by FIG. 50, but the display speed decreases to
one fifth.
[0242] FIG. 52 exemplifies peak values of two drive waveforms,
i.e., in the planar and focal conic drives, being respectively
changed linearly with temperature. Comparing with FIG. 50, three
curves are drawn between the upper and lower limits for the focal
conic state, the center line of which is the straight line
connecting the average of the upper and lower limit values of the
peak values for the focal conic state at the lower limit within the
operating temperature range, i.e., 0.degree. C., and that at the
higher limit, i.e., 50.degree. C.
[0243] The third embodiment is basically configured to use the
centerline for changing the peak value of the drive waveform in
terms with respect to temperature for the focal conic state. The
new margin of the peak value, required to fall between the upper
and lower values for the focal conic state as shown by FIG. 50 to
begin with, results in being larger than in the case of FIG. 50.
That is, within the above-described three lines for the focal conic
state, the upper line is the maximum value of the peak value within
the margin, while the lower line is the minimum value of the peak
value within the margin. The values within the margin relative to
the three lines are minimum 25.4 volts, maximum 32.6 volts and
average 29.0 volts at 0.degree. C.; and minimum 15.9 volts, maximum
23.7 volts and average 19.8 volts at 50.degree. C.
[0244] In FIG. 52, for the peak value of a drive wave form for the
planar state in the third embodiment, it is possible to change a
value, either by adding a prescribed value to the peak value of the
drive wave form for the focal conic state at the same temperature
or by multiplying a prescribed value therewith, with respect to
temperature. The aforementioned characteristic is shown by the line
drawn above the planar state in FIG. 52. Incidentally, the value of
this line at 0.degree. C. is 49.3 volts which is 1.7 times the
average value, i.e., 29.0 volts, of the three lines corresponding
to the focal conic state. Meanwhile, the value is 33.66 volts at
50.degree. C., which is 1.7 times average value corresponding to
the focal conic state, i.e., 19.8 volts.
[0245] FIG. 53 exemplifies a configuration of temperature
compensation circuit for voltage peak value of the planar and focal
conic drive described in association with FIG. 52. In FIG. 53, the
AMP1, that is, the amplification ratio of the amplifier receiving
the temperature sensor output is equal to R2/R1 (i.e., R2 divided
by R1) whose value is 1.7.
[0246] A sensor output at a certain temperature is computed by an
arithmetic circuit, not shown, and so the output values thereof at
0.degree. C. and 50.degree. C. are equal to the indication value of
the average of the three lines for the focal conic drive described
in FIG. 52. That is, the sensor output values are 29.0 volts at
0.degree. C., and 19.8 volts at 50.degree. C. Accordingly, the AMP1
output is 49.3 volts at 0.degree. C., and 33.66 volts at 50.degree.
C. These values are equal to the values on the temperature
compensation characteristic line for the planar state described in
association with FIG. 52.
[0247] The TR1 and TR2 each constitute an emitter follower circuit
for adequately lowering the output impedance, with each emitter
voltage, that is, the output value for the planar voltage for one,
and the focal conic voltage for another, are lower than the
respective transistor base voltages by about 0.7 volts. Therefore,
the planar voltage output value at 0.degree. C. is about 48.6.volts
(=49.3-0.7) and at 50.degree. C. is about 33.0 volts (=33.66-0.7)
which are adequately higher than the minimum value of the peak
value of the drive voltage waveform for the planar state, that is,
the minimum voltage, i.e., 43.3 volts at 0.degree. C. and 30.9
volts at 50.degree. C., for the planar state described in
association with FIG. 50.
[0248] The base voltage of TR2 is the value R4 times the output
voltage of AMP1 divided by (R3+R4). The value of this coefficient
is equal to 1/1.7 which is the emitter voltage of TR2, that is, the
output value of the focal conic voltage being 28.3 volts
(=29.0-0.7) at 0.degree. C., and about 19.1 volts (=19.8-0.7) at
50.degree. C. These values are represented by the three lines
described in association with FIG. 52 and are sufficiently larger
than the minimum voltage (25.4 and 15.9 volts, respectively) for
the focal conic state, and sufficiently smaller than the maximum
voltage (32.6 and 23.7 volts, respectively). Also, it is possible
to secure the same margin with the pulse width at 10 ms as with 50
ms by changing the peak values of the drive wave form for the focal
conic state linearly in terms of the operating temperature of the
LCD cell as described above. In other words, it is possible to
secure the same value as the margin for the peak value despite the
display speed being five times higher and operate the display
apparatus using the cholesteric LC stably over a wide temperature
range.
[0249] While the descriptions of the third embodiment have so far
been ranging from the power supply circuit, display function limit
circuit, and display-use power supply current regulation circuit
for a noncontact IC card, to the temperature compensation circuit
for a cholesteric LC drive voltage, these circuits will actually be
used in combination of some of them, rather than as individual
circuits independently. Such combinations can be made possible by
selecting some circuits on an as required basis.
[0250] It is also possible to determine the values of devices and
reference voltages for each circuit relatively easily. While a
detailed description such as the determination of resistance values
has been given herein for the temperature compensation circuit
shown by FIG. 53, the operation of the current regulation circuit
described for FIG. 49 for example can be found in a common handbook
or the like, enabling values for devices to be determined
easily.
[0251] As described above, the third embodiment accomplishes a
substantial cost reduction and slimming of power supply circuit for
a display panel using a cholesteric LC for example, avoidance of
shortening a communicable distance or operational instability by
limiting the display function in response to the supplied electric
power and stable and quick startup of an existing driver LSI
through regulating the current of a display-use power supply at
startup, thereby increasing applicable ranges of mobile equipments
greatly.
[0252] The subsequent description is of a fourth embodiment
concerned with a drive method for an LCD device and an image
display method used in a display apparatus using a semi-permanent
memory capable display device such as a cholesteric LC device. In
the fourth embodiment, the ensuing description deals with a drive
method and image display method for carrying out an LC device drive
and image display with the smallest possible power consumption in
order to use a display apparatus, for which a cholesteric LC is
utilized for example, in a non-powered condition.
[0253] FIG. 54 is a block diagram showing a driver for driving an
LCD device, such as a matrix type LCD device, according to the
fourth embodiment. The comprisal of the driver per se is
approximately the same as that of a commercially available existing
STN common driver for example. The characteristic of the fourth
embodiment is in its drive method rather than the comprisal of the
driver as a characteristic of the present invention.
[0254] Referring to FIG. 54, a power and data receiving unit 81
receives power and data sent from wireless terminal equipment 20
transmitting the power and data or an IC card reader/writer, a
signal control circuit 82 controls a signal conversion circuit 83
in response to the received result for driving and displaying a
matrix type LC device 84.
[0255] The matrix type LC device 84 comprises a scanning electrode
for commonly selecting a line and a signal electrode for providing
data, with the scanning electrode receiving a polarity reversed
signal FR for the purpose of making a drive signal an alternating
signal for the LC device, an Eio signal as a line selection signal,
an Lp signal for the purpose of latching data over at the signal
electrode and shifting a scanning line, et cetera; and with the
signal electrode receiving a data signal used for writing in
addition to the aforementioned FR signal and Lp signal.
[0256] The scanning electrode usually receives the Eio signal for
selecting a scanning electrode for the purpose of writing data line
by line from the top line, whose mode is called a common mode
herein. Comparably, it is also possible to provide data to be
called a segment mode for the purpose of writing data on a
discretionary line in lieu of writing data line by line from the
top line and also a signal for switching these two modes.
[0257] FIG. 55 describes a screen rewriting method according to the
fourth embodiment. A conventional common method has been to reset
the previous display screen in bulk when rewriting a screen, which
consumes power on the order of at least tens milli-Watts (10 s mW)
at the reset, resulting in a noncontact IC card consuming the power
substantially larger than the power supplied from an IC card
reader/writer, e.g., five to ten mW, making it very hard to carry
out a reset in bulk by a non-powered display apparatus.
[0258] Accordingly, the fourth embodiment is configured to reset in
units of several lines such as by four lines to repeat the
operation of writing data for one line simultaneously with
rewriting the screen, thereby suppressing the power consumption;
and use rewriting data per se as the reset-use data for resetting,
rather than using specific reset data such as converting all the
pixels to white.
[0259] Referring to FIG. 55, the bottom half of the screen shows
the screen of the previous display and the top half the screen of
the updated display, showing the state of the head writing line,
starting from the top line progressing line by line, as described
above, to the approximate center of the screen, while reset lines,
e.g., four lines, are being reset by using the writing data at the
same time that the data writing progresses on the writing line.
This operation will be described in more detail by referring to
FIG. 56.
[0260] Referring to FIG. 56, the first operation is to set four
lines as reset lines. In FIG. 56, as Eio and LP signals are
inputted simultaneously, the first line from the top of the screen
shown by FIG. 55 is selected, and the state becomes ready for
writing data on the line. Next, as the second pulse of the Eio and
Lp signals are both inputted, the initially selected first line is
shifted by the Lp signal so as to select the second line and at the
same time the first line is selected by the simultaneously inputted
Eio signal, thus the state is now such that the two lines, i.e.,
the first and second lines, are selected. A repetition of this
operation achieves a state of one to four lines being selected
within the reset line selection period, hence allowing data writing
in the four lines.
[0261] The subsequent pause line setup period is only inputted by
an Lp signal, thereby shifting one line, thus the second through
fifth lines in the screen assume the state of being selected.
[0262] In the beginning part of the subsequent writing period, Eio
and Lp signals are simultaneously inputted to shift the previously
selected second through fifth lines by one line respectively so
that the third through sixth lines assume the state of being
selected and at the same time input of an Eio signal makes the
first line in the screen, that is, the first line also assumes the
state of being selected. Providing data meant for the first line in
this state causes the data itself to be written therein and at the
same time the same data meant for the first line is provided to the
third through sixth lines for resetting the previously displayed
data therein. In this event, the second line is now a pause line
set up by the pause line setup period so that no data will be
written therein.
[0263] In response to the next Lp pulse input, the previously
selected line is shifted so that the second line and the fourth
through seventh lines assume the state of being selected. Providing
data meant for the second line in this state causes writing therein
with the data to be written therein and at the same time resets the
previously displayed data in the fourth to seventh lines.
[0264] A further input of the next Lp pulse selects the third line
and the fifth through eighth lines for writing data in the third
line. While the data meant for the first line was written to the
third line as a result of inputting an Lp pulse two pluses prior,
the response time of the cholesteric LC is generally on the order
of tens of milliseconds (10 s ms), with some variance due to
material characteristics. At the time of inputting an Lp pulse as
the timing for writing data to the second line, the third line is
in a pause period so that the pixels in the second line are in the
focal conic state, or in a state of transitioning to the planar
state in this period (e.g., 50 ms or less) and that a decision will
be made for either the focal conic state as an actual writing state
or the planar state at the time of actually receiving data for the
third line. Thus these operations will be repeated until data is
written to the 240.sup.th line for example, that is, the bottom
line of the screen.
[0265] The next description is of a different power suppression
method according to the fourth embodiment while referring to FIG.
57, which shows a signal to determine polarity reversing for an LC
device drive wave form described in association with FIG. 54. For a
cholesteric LC, it is generally desirable to reverse the polarity
of a pulse within a writing signal for one line. This is to resolve
the problems of deterioration of LC and degradation of image
quality (e.g., residual image or cross-talk). Other available
methods such as reversing the polarity per a plurality of lines, or
per frame, are not preferred due to residual images and display
noise caused by fluctuations of ions within the LC.
[0266] The upper part of FIG. 57 shows a polarity reversing method
for the conventional drive signal, which performs polarity
reversing by providing a positive pulse initially, followed by
providing a negative pulse. The waveform shown by the lower part of
FIG. 57 is the polarity reversing method according to the fourth
embodiment. Carrying out polarity reversing for a drive signal in
the form of providing a positive pulse to the first line initially,
followed by providing a negative pulse thereto while conversely
providing a negative pulse to the second line initially, followed
by providing a positive pulse thereto, hence reversing the polarity
in one line, while suppressing the power consumption due to the
reversing period being two times that of the conventional method
and preventing problems of display quality from occurring.
[0267] FIGS. 58 through 60 describe effects of drive methods
described by referring to FIGS. 55 through 57. FIGS. 58 and 59 show
effects of the fourth embodiment corresponding to FIGS. 3 and 4,
respectively, which have been described as the conventional
technique. Use of the above described drive method does not cause a
reduced contrast even when using a short pulse having a period of
about eight milliseconds for example, in place of a long pulse
having a period of tens of milliseconds, enabling high quality data
writing for a QVGA sized (i.e., 320 dots wide by 240 dots high)
screen by a drive circuit using low power on the order of five
milli-Watts.
[0268] FIG. 60 describes a power consumption suppressing effect
achieved by resetting several lines at a time, that is, four lines
for the configuration shown by FIG. 56, in lieu of a bulk reset,
according to the fourth embodiment. A bulk reset causes an extreme
increase in the power consumption at drive start, whereas the
fourth embodiment enables a suppression of such an increase in
power consumption.
[0269] The next description is of a skip drive method as an image
writing method according to the fourth embodiment while referring
to FIGS. 61 and 62. The drive method, that is, the skip drive
method is configured to write data for a pixel in a discretionary
position in a matrix by providing a signal for a segment mode to
the scanning electrode side as well, in lieu of the above-described
common mode.
[0270] Referring to FIG. 61, the first operation is to reset the
entire display screen. In this event, the entirety may be
transitioned to the focal conic state, except that the power
consumption will be large and therefore, the beneficial.sub.[adg1]
is a simple reset to an incomplete focal conic state by a short
pulse with a cycle of 3 ms or less. An alternative method may be to
segment the entire display into a plurality of blocks to reset by
block.
[0271] Next, the scanning electrode side selects parts for writing
with the same pattern, that is, a "white background" herein, and
writes in bulk to electrodes in these parts. This makes it possible
to write a white background pattern in a plurality of lines
simultaneously, thereby enabling a shortened drive time.
[0272] The aforementioned same pattern is not specifically limited,
but a pattern with a high spatial frequency, such as checkers,
increases the power consumption, and therefore it is necessary to
limit the number of lines to write in bulk according to the
pattern. In other words, the number of lines to be selected in bulk
will be reduced with the spatial frequency of the pattern.
[0273] There is a low possibility of the same pattern existing in
an image if the image is of random patterns as a result of image
processing by using an error diffusion method which diffuses an
error of a certain pixel to the neighboring pixels, whereas there
is a possibility of the same pattern existing in an image processed
by a systematic dither method as one kind of a binary dither method
which adds noise to a density signal of a halftone image to
binarize through threshold processing, or in a halftone image using
a dot pattern. The skip drive system, however, is particularly
effective for an image with many white background areas such as
text display.
[0274] Returning to FIG. 61, the writing in bulk of the same
pattern is followed by a normal sequential line drive (i.e.,
passive drive) for carrying out sequential writing of the remaining
parts other than those of the same pattern. In this event, the
adoption of interlace scanning makes it possible to recognize the
entire image more quickly. The skip drive is characterized by being
accomplished through the use of a simple drive circuit in lieu of a
complex method as with an MLA (multi line addressing) drive and
varying the number of lines to be driven in bulk depending on the
pattern.
[0275] FIG. 62 is a process flow chart of the skip drive method. In
FIG. 62, the left part is a flow chart of the same pattern
detection processing as pre-drive processing. This processing is to
perform binary screening by error diffusion processing by using an
eight-bit original image for example (step S1) (simply "S1"
hereinafter), select a scanning electrode as reference data for
comparison as the loop 1 (S2), select a scanning electrode as data
for comparison (S3), perform a pattern comparison of data for each
electrode (S4), judge whether or not the same pattern has been
detected (S5) and, if detected, store the coordinates or the
address where the same pattern exists in the same pattern address
storage memory 86 (S6). While if it is not detected, change the
scanning electrodes as data for comparison in S3 to continue the
processing, and when finished comparing the data of the scanning
electrode as reference data for comparison, which has been selected
in step S2, change the scanning electrode as reference data for
comparison in the step S2 to continue the processing until the
comparisons are done for all data when the processing ends.
[0276] The flow chart on the right side of FIG. 62 is at the time
of driving, that is, for write processing. In FIG. 62, as the
processing starts, the first operation is to perform a reset in
bulk for the entire display screen (S10), read one same pattern out
of the same pattern address storage memory 86 (S13), select
simultaneously a plurality of scanning electrodes for writing the
data pattern (S12) to, write data in bulk (S13), followed by
performing the processing of steps S11 through S13 for the next
pattern. When finished writing the same pattern, carry out a
writing loop for the lines to be written (S14) and perform passive
writing of data for the remaining part, which is yet to be written,
line by line (S15), to end display processing.
[0277] The next description is of a multi-value writing method
according to the fourth embodiment while referring to FIGS. 63 and
64. While a display apparatus using a cholesteric LC generally has
the problem of the entire image becoming low contrast with writing
speed because a transition to the focal conic state becomes
incomplete with a higher writing speed, the fourth embodiment,
taking advantage of such a characteristic, is capable of carrying
out a multi-value writing which repeats writing a halftone image to
obtain a clear display image.
[0278] First, let the case of three-value writing be described. The
first operation is to run a screening process with three values,
for example, 0, 128 and 255 for an image with a 8 bit 256-step gray
scale. Although the kind of such processing is not specifically
limited herein, to use of the above described error diffusion
method or a blue noise mask method as image processing for a larger
image area it be possible to generate a pseudo-halftone image with
a high resolution.
[0279] Following the three-value screen processing, extract pixels
of black (i.e., "0") level, that is, pixels to be basically written
as black, and run an initial scan for such pixels only, thereby
writing a halftone image. That is, driving the LC device faster
than usual carries out image writing of halftone level in a state
of fixed output voltage of the driver. An adjustment of drive speed
can obtain an image with halftone data being written in pixels for
which black is supposed to be written as shown by FIG. 63.
[0280] Subsequently, the second scan, that is, writing data which
is converted from a black (0) level and intermediate level (128) to
the black (0) level changes pixels which were a gray halftone
before, as shown by FIG. 63, are now a black halftone, and with
other parts being written as a gray halftone or white halftone,
thereby forming a three-value image eventually. This makes it
possible to display a multi value halftone image easily and at the
same time the user is also able to grasp the entire image of the
display quickly. That is, a blurry initial image becomes gradually
clear and hence a multi value image, more than 3 values, can be
accomplished by a number of write operations at a suitable scanning
speed. Also, conversely, it is possible to write cumulatively by
starting at a gray halftone followed by adding pixels for moving
toward a white halftone.
[0281] As described above, the fourth embodiment makes it possible
to suppress the power consumption a great deal of driving and
display a high quality image in a short time without allowing a
residual image or a reduced contrast in a non-powered display
apparatus using a display device which has a semi-permanent memory
property such as a cholesteric LC.
[0282] The description now proceeds to a fifth embodiment. In the
fifth embodiment, the description concerns a more detailed
comprisal and wider range of application of the display apparatus
with a semi-permanent memory property such as a cholesteric LC for
example. In the fifth embodiment, an automatic display apparatus,
at least comprising a display medium having a semi-permanent memory
property which retains display content even if power is shut off,
memory for retaining information relating to an acquisition method
for data to be displayed and information relating to a display form
of the acquired data, an Internet connection unit, for example, for
acquiring display data based on the data acquisition method, and a
control unit for displaying the acquired data according to the
retained display form, acquires display data after being started in
response to an instruction given externally or internally and
carries out data display on a display medium with a semi-permanent
memory property by adjusting a display form.
[0283] FIG. 65 shows such an automatic display apparatus. In FIG.
65, an automatic display apparatus 90, comparing with the wireless
display panel 21 shown by FIG. 7 for example, comprises a power
supply 91, an Internet connection unit 92, a battery 93, a timer 94
and nonvolatile memory 95 in addition to the control unit 35,
display unit drive circuit 39 and memory capable display unit
40.
[0284] In FIG. 65, the automatic display apparatus 90, being
furnished with a host function and mechanism for connecting to the
Internet, acquires page data by the operation of the Internet
connection unit 92 by using a URL stored by the nonvolatile memory
95 following the power supply 91 being turned on and displays the
page data in the memory capable display unit 40 according to the
display form information stored by the nonvolatile memory 95,
followed by transition to a power off state automatically. The
content of the nonvolatile memory 95 is freely rewritable from a
wireless terminal for example. Alternatively, the timer 94 backed
up by the battery 93 can start the automatic display apparatus
90.
[0285] Note here that, in claims herein, a display unit corresponds
to the memory capable display unit 40, a storage unit corresponds
to the nonvolatile memory 95 and a control unit corresponds to the
control unit 35 and display unit drive circuit 39, all of which are
noted by claim 25. Also, in claim 30, a nonvolatile storage unit
corresponds to the nonvolatile memory 95 which can store display
data for a plurality of pages to rewrite the content of the memory
capable display unit 40 and to restore a content which has been
displayed by the memory capable display unit 40 by using the
content of the nonvolatile memory 95 if the content is erased by
some cause.
[0286] FIG. 66 is an example comprisal of an automatic display
apparatus connected with a communication terminal 97 such as a PC,
PDA, et cetera, through wired communication. In FIG. 66, the
automatic display apparatus 90 and communication terminal 97
comprise wired interfaces 96 and 98, respectively, such as a USB
and contact type IC card. Once connected with a PC or slot-in type
or cradle type IC card reader/writer, the automatic display
apparatus 90 receives power to start up, operates itself as in the
case of FIG. 65 followed by transition to a ready state
automatically; and the power will be cut off once the connection
with a PC, et cetera, is cut off. The content of the nonvolatile
memory 95 can be freely rewritten over at the host, that is, the
communication terminal 97 by way of the wire interfaces 98 and 96.
A continuous connection between the automatic display apparatus 90
and communication terminal 97 will enable an automatic startup by
the timer 94 for example.
[0287] FIG. 67 is an example comprisal of an automatic display
apparatus wirelessly connected with a communication terminal. The
automatic display apparatus 90 and communication terminal 97
respectively comprise wireless interfaces 100 and 101 applicable to
a wireless LAN or Bluetooth so that the automatic display apparatus
90 starts up in response to a received startup command from the
communication terminal 97 to carry out the same operation as in the
case of FIG. 65. A battery powered monitor (not shown herein) can
be comprised for continuously monitoring for a startup command from
the communication terminal 97 so that a startup command issued by
the "timeout" of a timer (not shown) equipped over at the
communication terminal 97 automatically starts up the automatic
display apparatus 90.
[0288] FIG. 68 is an example comprisal of an automatic display
apparatus equipped with a noncontact IC card interface. The
automatic display apparatus 90 comprises a noncontact IC card
interface 102 or an RF (radio frequency) ID interface, and also the
communication terminal 97, e.g., IC card reader/writer, comprises a
noncontact IC card interface 103.
[0289] When the distance from the communication terminal 97 becomes
a prescribed value or less, the automatic display apparatus 90 is
started up to operate in the same way as in the case of FIG. 65.
Noncontact IC cards can be of a proximity type, which is applicable
to a short communicable distance of about 10 cm with a higher
communication speed, or a neighborhood type, which is capable of a
long communicable distance of about 1 m with a lower communication
speed. The automatic display apparatus 90 can be equipped with both
types of IC card chips, in which case it is practical to shut off
power to a display unit completely and transmit character data
only, not image data, due to the limitation of communication speed
in long distance communication where only the neighborhood type is
capable of functioning properly because of the power supplied by
the communication terminal 97 becomes small in such a case.
[0290] FIG. 69 exemplifies information about an acquisition method
for data to be displayed and information about a display form for
the acquired display data, both of which are stored by the
nonvolatile memory 95 shown by FIG. 65 for example. In FIG. 69, a
URL or path to the file is stored in the addresses 0 through 255 as
a method to obtain a data to be displayed. The content is a URL
such as xxxxx.com. The addresses 256 and thereafter are data
relating to display forms, storing the display form data, such as a
specification for the number of pixels, portrait or landscape
orientation of the display screen, size for size enlargement or
reduction, et cetera, which resemble common printing form data.
[0291] The fifth embodiment is capable of carrying out not only
data display but also displaying an update date and time of data.
FIGS. 70 and 71 describe an update date and time display form. FIG.
70 shows the case of the display apparatus comprising an update
date and time display unit therein using segment pixels independent
of the display unit for data per se. The update date and time
display unit can also use a cholesteric LC.
[0292] FIG. 71 describes the case of the data display unit
displaying an update date and time. This display is as a result of
the host (e.g., communication terminal) side adding the update date
and time to the display data prior to the transmission. In
comparison to the above, the host side transmits the display data
and the update date and time information independently in the case
of FIG. 70. A display of the update date and time enables the user
to determine the time stamp of the information instantly.
[0293] Further description continues for another example comprisal
of the automatic display apparatus according to the fifth
embodiment. First, while the memory capable display unit 40 shown
by FIG. 65, et cetera, is most preferably the one with a
semi-permanent memory property such as the above described
cholesteric LC, it is possible to use a device capable of retaining
the memory content for a unit period of several hours or one day
for example, instead of having the semi-permanent memory property,
or combine a device having no memory property with a nonvolatile
memory.
[0294] In this case, it is possible to have a size equivalent to
one page or plural pages of nonvolatile memory. In the case of a
display device having a semi-permanent memory property, such buffer
memory is not necessarily required, but equipping of one of page
buffer memory will make it possible to restore display content
instantly if a part, or the entirety, of the display content of the
display device disappears due to exceeding the upper temperature
limit of the memory property for example. The equipment of buffer
memory for plural pages also makes it possible to switch the
display contents instantly.
[0295] The automatic display apparatus is also capable of
inhibiting rewriting of the data displayed by the memory capable
display unit 40 shown by FIG. 65 for example. The method for
inhibiting rewriting can naturally be through a hardware method
such as the write inhibit method used for a flexible disk (i.e.,
floppy disk) for example, or a software method.
[0296] Meanwhile, if a communication with an external entity is
interrupted in the middle of the automatic display apparatus
operating to acquire display data provided externally, it is also
possible to acquire a part of the display data yet to be acquired
when the communication with the external entity resumes. Such a
method is widely put into practice by way of a download manager
such as are available as freeware. A resume function included in
such a download manager can be used for acquiring the data yet to
be acquired.
[0297] Furthermore, the automatic display apparatus according to
the fifth embodiment may comprise a storage function for a history
relating to a display data acquisition method. While such a
function is not necessarily required, equipment with such a
function can easily reference past display data. Such a history can
of course be stored in the nonvolatile memory 95 shown by FIG. 65
or externally by way of the host apparatus.
[0298] Last but not least, the descriptions are of diverse
applications of the automatic display apparatus according to the
fifth embodiment. In summarizing such applications, it is possible
to transmit not only a mobile terminal screen as is to the
automatic display apparatus, but also high resolution large screen
data specifically built and transmit it to the automatic display
apparatus.
[0299] The automatic display apparatus may also comprise an
installer for a mobile terminal in order to install a driver for
the automatic display apparatus on a mobile terminal from the
automatic display apparatus. A mobile terminal generally has a
small memory size, which can be used effectively by installing the
driver only on as required basis and discarding it as soon as the
necessity ends.
[0300] The automatic display apparatus may also be formed as a
refill corresponding to replaceable pages for a day organizer, both
sides of which can display data. In this case, installing antennas
on both sides, comprising a magnetic shield layer in the middle,
and comparing the voltages generated for the two antennas to
rewrite the display data first for the side on which the higher
voltage antenna is installed.
[0301] The automatic display apparatus may further allow the
display unit containing the display panel and driver LSI to be
detached thereof, comprise the function of erasing data of the
display panel and buffer memory, or let a part of the display
screen be a fixed advertisement display area so as to display in
the area by downloading advertisement data at the time of updating
the display data by a prescribed procedure.
[0302] Further descriptions of these example applications will be
given while referring to the accompanying drawings. An automatic
display apparatus shown by FIG. 72 (i.e., wireless display sheet
and wireless display card) is equipped with a noncontact IC card
interface (i.e., antenna and IC chip). When positioning the
automatic display apparatus close to a mobile phone, digital camera
or PDA, which is equipped with an IC card reader/writer, the
automatic display apparatus requires transmission of display data.
The mobile phone, et cetera, being installed by a driver for the
automatic display apparatus, transmits mobile phone screen data as
is to the automatic display apparatus, or after building up high
resolution large screen data based on the mobile phone screen data.
The automatic display apparatus carries out display drive control
in response to the power supplied from the mobile phone as
described above to display the screen data in the display panel,
followed by automatically transitioning itself to a ready
state.
[0303] Just moving a sheet type material close to a mobile phone
displays an enlarged map, the entirety of a long mail message or
content to be memorized, thereby providing a real convenience. A
driver for the automatic display apparatus for a mobile phone can
also be installed from the automatic display apparatus.
[0304] When positioning an automatic display apparatus shown by
FIG. 72 close to a laptop PC equipped with an IC card
reader/writer, the automatic display apparatus requires
transmission of print data. The laptop PC, having a driver for the
automatic display apparatus installed, transmits the printing data
to the automatic display apparatus in a usual printing procedure.
The automatic display apparatus carries out a display drive control
in response to the power supplied from the laptop PC to display the
printing data in the display panel, followed by automatically
transitioning itself to the ready state.
[0305] An automatic display apparatus may be formed as a refill for
a day organizer, which may be configured as capable of duplex
display. Installing antennas on both sides with a magnetic shield
in the middle, it is possible to identify on which side an IC card
reader/writer is located. It is desirable to assign priority of
data processing to the side where the IC card reader/writer is
located.
[0306] FIG. 73 shows an automatic display apparatus, being a second
display for a PC, comprises a USB interface. When connecting the
automatic display apparatus to a desktop PC, the former requires
transmission of screen data as the second display or thereafter.
The desktop PC, having a driver for the automatic display apparatus
installed, transmits screen data to the automatic display apparatus
as with a usual display. The automatic display apparatus displays
the screen data in the display panel, requires transmission of the
subsequent screen data automatically and repeats the series of
operation.
[0307] The fact that the use of a plurality of displays increases
the efficiency of work is well known. One can use four or five of
the automatic display apparatus in taking advantage of the aspects
thereof such as: its being thinner, lighter and taking less space
than the conventional display; allowing use in a free layout; and
is less expensive as compared to the usual display. It is a
required item for comfortably reading an online manual with deep
nesting.
[0308] Next, an automatic display apparatus according to the
present embodiment is equipped with a wireless LAN interface and a
battery. The automatic display apparatus starts up automatically
when the owner's desktop PC is started up followed by completing
authentication of the owner. The automatic display apparatus
requests the desktop PC to transmit personnel schedule chart data.
The desktop PC, having a driver for the automatic display apparatus
installed, transmits the personnel schedule chart data. The
automatic display apparatus displays a personnel schedule chart in
the display panel, followed by transitioning itself automatically
to the ready state in which the display unit of the automatic
display apparatus can be detached.
[0309] Quite a few personnel print a personnel schedule chart every
day, consuming approximately 250 sheets of paper a year per person.
A use of the automatic display apparatus not only saves the time
and effort required to print a personnel schedule chart but also
reduces paper consumption and paper waste volume.
[0310] An automatic display apparatus according to the present
embodiment is equipped with a noncontact IC card reader/writer
(i.e., antenna and IC chip). When positioning the automatic display
apparatus close to a mobile phone equipped with an IC card
reader/writer, the automatic display apparatus requests
transmission of a newspaper article. The mobile phone, having a
driver for the automatic display apparatus installed, downloads the
newspaper article from the newspaper home page to transmit to the
automatic display apparatus which carries out display drive control
in response to the power supplied by the mobile phone to display
the newspaper article in the display panel, followed by
transitioning itself to the ready state.
[0311] Just positioning a sheet shaped object close to the mobile
phone enables a reading of the latest newspaper article, providing
great convenience. The same technique can be applied to an
electronic book. There is no need of a pre-download, hence making
it possible to start reading a paperback book or magazine on
hanging poster in trains, which has caught the eye right then and
there. This practice is much more convenient and comfortable as
compared to an electronic book by the method for downloading onto a
secure digital (SD) card for the purpose of protecting a
copyright.
[0312] An automatic display apparatus according to the present
embodiment is equipped with a wireless LAN interface and a battery.
The automatic display apparatus starts up automatically when
starting up the owner's desktop PC, and requests the desktop PC to
transmit a newspaper article. The desktop PC, having a driver for
the automatic display apparatus installed, downloads the newspaper
article from the newspaper home page to transmit to the automatic
display apparatus which then displays the newspaper article
according to the size of display panel (i.e., A6 through a two-page
spread of A3 sizes), followed by transitioning itself to the ready
state. The automatic display apparatus allows the display unit to
be detached in the ready state.
[0313] Use of the automatic display apparatus eliminates printing,
delivery or distribution to each subscriber (including private
homes), providing news at a less expensive subscription fee, as
well as much more timely news articles, as compared to conventional
newspapers, while reducing paper consumption and paper waste
volume.
[0314] Many automatic display apparatuses shown by FIG. 74, each
comprising a Bluetooth interface and a battery, are either hung or
stuck in passenger train cars. One of the automatic display
apparatuses starts up by the built in IC identifying a startup
instruction issued by a Bluetooth enabled laptop PC brought in the
passenger train car to request transmission of advertisement data.
The laptop PC, having a driver for the automatic display apparatus
installed, transmits the advertisement data to be displayed to the
started automatic display apparatus, which then displays the
advertisement in the display panel, followed by transitioning
itself to the ready state. A series of operations will be repeated
until the completion of display content updates for all the
applicable automatic display apparatus.
[0315] A use of the automatic display apparatus reduces printing
costs, installation costs, paper consumption and paper waste
volume. A continued installation of a PC in a train car will enable
switching of advertisements in response to the time of day, running
zone of the train service, et cetera. The same technique can be
applied to merchandize price displays at a store such as a
supermarket.
[0316] Next, many automatic display apparatus used for a building
wall advertisement are hung on a building wall, with each
comprising a Bluetooth interface and a battery. A Bluetooth enabled
laptop PC is installed in the building and connected with antennas
installed in a plurality of places on the wall. One of the
automatic display apparatuses starts up because of a startup
instruction issued by the laptop PC to request for transmission of
advertisement data. The laptop PC, being installed by a driver for
the automatic display apparatus, transmits the advertisement data
to be displayed by the started automatic display apparatus which
then displays the advertisement in the display panel, followed by
automatically transitioning itself to the ready state. A series of
operations will be repeated until completion of display content
update for all the applicable automatic display apparatus. In the
case of a plurality of automatic display apparatuses displaying a
large screen, each display requires only the image data for the
assigned part, and therefore image cutout processing is easy.
[0317] Use of the automatic display apparatus reduces printing and
installation costs. It is also possible to switch the advertisement
contents entirely depending on the time of day. The same technique
can be applied to the train schedule at a station.
[0318] Many automatic display apparatuses for use as a handout at a
conference shown by FIG. 75, each comprising a Bluetooth interface
and a battery, are furnished in a meeting room. One of the
automatic display apparatuses starts up because of a startup
instruction from a Bluetooth enabled laptop PC brought into the
meeting room to request transmission of meeting material. The
laptop PC, having a driver for the automatic display apparatus
installed, transmits the meeting material to be displayed to a
started automatic display apparatus which then displays the meeting
material in the display panel, followed by transitioning itself to
the ready state. A series of operations will be repeated until all
the applicable automatic display apparatuses are displaying the
meeting material.
[0319] Use of the automatic display apparatus reduces printing
costs, book binding costs, paper consumption and paper waste
volume. Suddenly required material during the meeting can be
distributed in no time. Furthermore, the use of the automatic
display apparatus improves security by taking advantage of the
capability to erase the display panel and buffer memory data of any
classified material as soon as the meeting is adjourned.
[0320] The next description is of a usage example of a mobile
display having an advertisement display function. This is similar
to the screen enlargement display for mobile equipment as shown by
FIG. 72, whereas the difference therefrom is that a part of the
display screen is now a fixed area for an advertisement display.
Advertisement data is downloaded from a prescribed URL to display
in the advertisement display area at the time of updating display
data. This is very effective as a sales promotion tool and
therefore there is a high probability of enterprises distributing a
large number of the automatic display apparatus free of charge.
[0321] As described above, the fifth embodiment is comprised to
accomplish an automatic display apparatus using a convenient
electronic paper which highly integrates the characteristics of
starting up the automatic display apparatus without operating a PC,
et cetera, having the latest information displayed by positioning a
noncontact IC card close to an IC card reader/writer equipped in a
PC or PDA for example and retaining the display even if the power
supply is cut off with the characteristic of the display content
being discretionarily rewritable.
[0322] The present invention is applicable to not only industries
producing IC cards, electronic papers, liquid crystal display
devices and mobile equipments including mobile terminals and
digital cameras, but also all industries using these display
apparatuses, display devices and mobile equipment.
* * * * *